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everlearning
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Posted: Wed Jul 30th, 2008 06:33 am |
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We have a 2 yr old 30 gallon Bradford White Residential gas (propane) Water Heater (model # is M430T6FCX ) providing hot water to the bathroom and to a thermostat controlled baseboard radiator in an adjoining room.
In the last two weeks we've been noticing problems with diminishing hot water. The quantity of water is fine; it's the temperature that is diminishing.
(I know very little about plumbing, so please be patient as I try to do my best to explain everything I've observed.)
This exact problem of dimishing hot water has happened before. We had an older, cheaper Home Depot water Heater with little insulation. Our plumber replaced the water heater with this Bradford White heater and made some changes to the plumbing configuration as it had not been correct. And I also vaguely remember something about a valve being stuck .. being calcified... and that he'd replaced it with one made of a different material... maybe plastic? that he thought would resist getting calcified. He might have said something about backflow?? I can't quite remember. Sadly, that plumber is no longer with us.
Here's the details of what is now happening:
If the radiator is shut off (and therefore not calling for water), the bathroom water turns from hot to warm and decreases in temperature so that one needs to adjust the cold water flow in the shower every 30 seconds and after a few minutes, shut off the cold water faucet entirely. Within 5 minutes, the water is at 90 degrees and we're hustling out of the shower! With each day it gets worse: the time that we have hot water is less and the hot is getting less hot. (We used to be able to take long hot showers).
If the radiator is turned on (and calling for water), the bathroom water provides hot water.... though I am now noticing that the hot water, while nicely hot at first, is not lasting as long as it used to... I can get a pretty good shower, but not a long, Hollywood shower like I used to be able to get.
The diminishment of heat, though, is nothing like as dramatic as it is when the radiator is turned off.
I'm not sure if this is related or co-incidental, but last week the water heater was noisily releasing water thru the overflow pipe and the TP pressure valve was bouncing around. This happened maybe twice a day (that we knew about)... usually in the pre-dawn hours (so noisy it woke me up), and again in the early evening. Though the tank was set to high, the water that was coming out of the overflow pipe was barely hot, maybe 100 degrees. (I don't know if the radiator was turned on or not)
A plumber came and replaced the TP valve. It was clearly heavily calcified. He turned down the heat from where it had been - Hot - to the mark that represents 120 degrees. Still, a few hours later, the water heater again released a continuous strong stream of water as the TP valve moved in increments counter clockwise. (like 6'oclock, chug, gush, 4 o'clock, chug, gush; 2 o'clock etc... all the way round and then some, til it slowed and the water flow stopped). The TP valve was, however, much, much more quiet as it rotated.
The one negative to it being quiet, was that I couldn't hear if it was activated and since the overflow hose streams to the outside into the garden, i couldn't readily see evidence of its activity. My best guess though is that after that last overflow it didn't happen anymore. A couple of days later, to confirm this, I put some towels by the overflow to see if they got wet, and they didn't.
The plumber said that water heaters aren't made to heat radiators and that it all should be disconnected. Short of that, he said the water heater was fine and there was nothing he could do. (though he did end up replacing the TP ... which was good since it was so calcified)(He didn't take anything apart or look inside any of the water heater. He just looked at it from the outside)
He said it would have helped if he could have seen the TP valve trigger the overflow, but it didn't do it while he was there.
After he left, I studied the manual. The manual shows diagram piping configuations for "installation of gas water heaters suitable for water heating and space heating" So I now I'm not at all sure of his opinion. Also, our other plumber had said, it was unconventional, but workable.
As of today, the TP valve is no longer activating, but what is happening now is that If we set the water heater to high, the water heater turns itself off within 30 minutes. (This happens with or without the radiator on). ( It didn't do that last month or the month before.) It doesn't shut itself off if we set the water heater to the 120 degree mark or one notch above that. (When I say that it shut itself off, I think the pilot went out. I relit the pilot and turned the burner back up each time.... only to find it cold 30 minutes later... not pumping any hot water to the radiator)
We tried emptying the water heater. Interestingly, with the hot water faucet open in the bathroom, the water heater wouldn't drain a drop. . We had to have the cold water faucet open too. (We drained the tank completely, partially refilled it, and then drained that as well. We saw no sign of sediment.)
Here is how the water heater is set up. This is an old stone cottage. The water heater is housed outside the house in a stone walled shed that shares a wall of the bathroom.
It is top plumbed. The cold water pipe bringing in cold water to the water heater, first branches to the bathroom and then continues to the hot water tank. The hot water pipe leaves the hot water tank, has a branch going to the bathroom, followed by a shut off valve, and then runs to the radiator. Another pipe comes out of the radiator, and runs back to the water tank, with a branch entering the water tank just a few inches from the ground, before it ends with a faucet (for emptying the tank.)
After reading the lingo page, I realized that I haven't noticed and did not include info about the valves-where they are located and what kind- and that sounds like crucial info. I can look at those tomorrow and attempt to describe where they are.... you do need that info, right?
Otherwise, that's everything I can think of.
Is the new plumber right, and we must tear it all out or is the problem a valve as it was before... and if so, what do we do?
Thanks much for you patience in reading my efforts to give you all the clues and evidence you might need to solve this. And thank you for any suggestions.
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elenano
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Posted: Wed Jul 30th, 2008 09:08 pm |
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I cannot answer all your question, although I think some of my colleagues can. But check valves can "lime up" and stick open and cause such problems. That's one thing to check for. A spring check valve is less likely to do this than a swing check, but few people use them.
The other thing is that I would test for thermal expansion. You can find the procedure for that under Tanklets (link at the top of this page) in the Temperature/Pressure Relief Valves section.
Randy Schuyler
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energyexpert
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Posted: Fri Aug 1st, 2008 08:06 pm |
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I tried drawing a sketch of your system. Is there a pump somewhere to pump water to the baseboard radiator? If the pump (if one exists) is located on the hot water line before the tee to the bathroom then when the thermostat controlling the baseboard radiator stops the pump the stopped pump chokes off hot flow from the HW. Hot flow to the bathroom will then be cold water into the WH mixing with hot and then flowing out through the radiator return line (bottom of WH), through the radiator, through the tee, and then to the bathroom.
If there is a pump I think it needs to be on the radiator return line.
If there is no pump, I would put a check valve on the HW line to the radiator after the tee. This will keep water from back flowing from the radiator return line to the bathroom.
David
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everlearning
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Posted: Sat Aug 2nd, 2008 06:36 am |
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David
Re a pump: there isn't anything next to or nearby the water heater.
I do see a small metal round chamber next to the radiator itself. Could that be a pump?
It is placed AFTER the tee to the bathroom.
See photo

.Attachment: baseboard radiator.jpg (Downloaded 100 times) Last edited on Mon Aug 4th, 2008 06:07 am by everlearning
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everlearning
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Posted: Sat Aug 2nd, 2008 07:36 am |
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On the cold water line, I see what might be two valves.
Both of which are after the t where the cold water pipe goes to the bathroom. They are about 4" before the cold water pipe enters the tank.
One has a round smooth top. The other has a round top with a four sided lump stickiing out the top.
See photo of the valves on the cold water line below.
Are these indeed valves?
I touched the cold water pipe where it enters the tank and it was Very warm to the touch.
JillAttachment: valves on cold water.jpg (Downloaded 94 times) Last edited on Sat Aug 2nd, 2008 07:34 pm by everlearning
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everlearning
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Posted: Sat Aug 2nd, 2008 07:54 am |
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Randy, David
re valves on hot water pipes. All the hot water pipes are covered with pipe insulation so it's hard to see. I see only one place with a bump that suggests there could be a valve ... or something?? ... on the hot water line to the bathroom, (after it's t'd off the hot water line).
It's in a hard place to see or get to, behind the water heater: a lump covered with insulation... I taped the top with a stick and it feels solid, so I guess it's not just excess insulation tied off But to get to this, one would have to pull out the water heater! No way I can reach it.
So this is on the hot water pipe after it's t'd off to go to the bathroom. The pipe is going horizontally away from the heater toward the bathroom, then does a right angle down (presumably on its way to the bathroom), but when it does that right angle down, that's where there's this vertical upwards part/ lump (a short bit that goes upward) is swathed in the insulation, the end of which is folded over.
Photo below
Thoughts?
Attachment: hot water pipe lump.jpg (Downloaded 73 times) Last edited on Sun Aug 3rd, 2008 12:28 am by everlearning
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everlearning
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Posted: Sat Aug 2nd, 2008 08:25 am |
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I've been thinking about valves lime-ing up and sticking in an open position.
Remembering the calcification on the TP (which the plumber replaced), it would seem logical that the same calcification would be inside the pipes on a valve.
(Could that whole thing of the TP valve being set off and water being released have been caused by calcification around the TP valve... making that one symptom of the calcification. )
The system used to work fine, so something has changed. A stuck open limed valve seems a logical change.
And that would fit with what I had vaguely remembered the plumber saying when he came two years ago when we had the same symptoms (of less and less hot water. )
We use well water with, I understand, a high mineral content. No water softener.
JillLast edited on Sat Aug 2nd, 2008 07:59 pm by everlearning
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everlearning
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Posted: Sat Aug 2nd, 2008 08:03 pm |
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Randy,
I can't test for thermal expansion until I get a gauge. That may not be possible til next week.
But if it didn't have a pressure problem before (when it worked ok), why would it now?
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elenano
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Posted: Sun Aug 3rd, 2008 04:27 am |
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The first picture you sent is of a recirculation pump. The second is of a swing check valve. As to the third, I can't see through the insulation either.
Randy Schuyler
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everlearning
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Posted: Sun Aug 3rd, 2008 05:01 am |
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Randy,
Funny guy! ... just shows how high my expectations were of your abilities!
Well now we know that the cold water pipe has a check valve and the radiator has a recirculating pump, we have another two pieces of the puzzle, right?
But I still don't understand what's happening.. If the check valve is stuck in an open postion on the cold water input pipe, why would that make the shower temp drop when the radiator isn't calling for heat? Would it?
And why did we have to open the COLD water faucet in the bathroom in order to drain the tank (nothing happened with the hot water faucet open?
And what should I do next?
Jill
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eleent
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Posted: Mon Aug 4th, 2008 12:18 am |
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Hello: There is a lot to try and make sense of. So, looking at the basics first, It sounds like there is some sort of back flow or ghost flow that's allowing cooler water from the bottom of the tank to mix with warmer water. There could be unintended flow through the heating side of the system.
You should know that mixing domestic and heating waters is considered a no-no. It opens up the possibility of bacteria, specifically legionnaires, getting into the water one could ingest or breathe. Systems are usually separated by putting a heat exchanger between different waters. It's more expensive to do it that way, but is cheap compared to a hospital visit.
One of the photos is of a check valve. If it really is in the position shown, the disc inside could never work properly as it would hang open. For water running down through a vertical pipe, a spring check is needed.
There is some pressure problem or the T&P would not be operating and letting out only warm water. That gauge is needed. You're on a well, but is that on a pressure tank or gravity feed? If it's a pressure tank, controls for the pump pressure may be out of whack. Also, there may not be a working expansion tank in the system. That all affects the T&P.
If you have a way to isolate the heating side of things, (by closing valves) you can then see if you get good hot water to the shower. If so, that tells you the problem lies with unwanted flow in the heating system.
It would be nice to have some sort of drawing showing the layout of all the bits and pieces, but that is a tall order. For now, isolating the heating side and doing that test along with getting some pressure readings could provide some good info for moving forward.
Yours, Larry
Last edited on Mon Aug 4th, 2008 06:24 am by eleent
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everlearning
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Posted: Mon Aug 4th, 2008 05:05 am |
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Larry,
No, I didn't know how much of a no-no this is. The plumbing was conceived and first plumbed by my inventor landlord, who was thinking to take advantage of the heat generated by the water heater to heat my little office. He is brilliant and creative, but not a plumber. It was then modified by our now departed plumber, and I do vaguely remember his talking about potable and non-potable water and that this was not conventional. He reconfigured things to make them more acceptable, he said. But it sounds like it's still not kosher. Breathing bacteria in a steamy shower isn't good, and Legionnaires is serious, indeed. I will pass this info on to my landlord when he returns to town. Perhaps we won't be able to use a radiator to heat my office...
but one step at a time... as we figure this all out. And I learn!!!
I'll get info re pressure and whether we're on a pressure tank or gravity feed, etc.
The check valve photo is indeed correctly oriented. That pipe is a vertical pipe. (So clearly that valve would need to be changed to a spring check.)
I've attempted a drawing!!! (I'd have liked to color the hot pipes red and the cold pipes blue, but couldn't figure out how to do that. This is my first time using software drawing tools). It's obviously not to scale, but does this help??? If something needs clarifying, let me know, so I can either explain or redraw it. (I actually don't know which pipe the recirculating pump is on... the incoming or outgoing... it's hard to tell. So that part of the drawing is not accurate.)
I've turned off the shut off valve on the hot water line that takes the hot water to the radiator and turned down the radiator thermostat so it is not activating the radiator. Looking at my drawing, do you think that will isolate the hot water as you suggest? Or did I ideally need another shut off valve at the point where the water re-entered the tank?
I'll report results and other info as I get it.
Gratefully, JillAttachment: plumping drawing.jpg (Downloaded 50 times) Last edited on Mon Aug 4th, 2008 07:00 am by everlearning
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eleent
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Posted: Mon Aug 4th, 2008 06:53 am |
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Hello: Nice drawing! You're hired  It's good the check valve doesn't work as it would create pressure problems in the hot side plumbing if it did work. I'd just remove it and the capped pipe to clean things up. Closing that valve in the line to the heater, and unplugging power to the pump will likely have an effect. I'm imagining it will be a good effect as that is a perfect set-up for ghost flow as it is now. A spring check in that heater line could help stop unintended flow and allow it to be used. Closing only the one valve works for this test as it will essentially stop flow through the heating loop. Better would be a valve on each side so one could work on the system without shutting off the hot water.
Mixing heating and domestic water is OK only if bacteria cannot get a toe-hold. If water is circulated often through the heating loop, the water cannot go stagnant. The problem is timers and good intentions often don't live up to expectation. It's best to design systems that cannot misbehave and that's where a heat exchanger fits in. At least then it becomes a fail safe system.
Yours, Larry
ps. There should be an arrow on the pump, pointing in the direction of flow  , though I can say from the photo, water moves from left to right.
Last edited on Mon Aug 4th, 2008 06:56 am by eleent
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everlearning
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Posted: Mon Aug 4th, 2008 07:26 am |
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Larry,
Glad you liked the drawing. : ) Looks way better than my hand drawing! (Computers are so much fun!)
I'm looking at the pump. Yes, I see the arrow!
So, with the pump moving water from left to right, that means it should be drawn so that it's on the pipe that has come from the water heater - (I have it drawn on the pipe that is returning water to the water heater). If I get a chance, I'll fix that.
re water not going stagnant. In the winter, this would not be a problem as the heat is on often. However, when it's truly summer, and I don't need heat, the radiator won't be circulating. So then we'd have a problem.
I'll report shower results tomorrow!
JillLast edited on Tue Aug 5th, 2008 03:59 am by everlearning
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shashalou
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Posted: Mon Aug 4th, 2008 04:27 pm |
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Hi. The check valve is preventing expansion of the water into the well pressure tank or city line. The tpr valve probably blows often when the hot water is not used domestically.
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everlearning
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Posted: Tue Aug 5th, 2008 04:11 am |
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Larry,
Here's today's shower report.
With the shut off valve closed on the hot water pipe leading to the radiator as shown in the diagram, and with the radiator thermostat turned as low as possible so the radiator isn't calling for water, and the water heater temp set one notch above the mark (the mark I am told represents 120 degrees), I took a great hot shower of steady temp. However, I was so delighted with the shower that I lost my scientific logging focus and forgot to clock the time!
So, I waited a couple of hours and ran water in the sink, checking time and temp. With the hot water tap open full, It ran at at least 120 degrees, (it felt hotter than that at first but my thermometer only goes to 120) for a full 15 minutes. Towards the end I the temp was a hair under the 120 mark.
Should I do it longer or repeat?
So, that confirms that it isn't a thermostat problem or a heater problem, but rather a piping/ valve problem, right?
Jill
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everlearning
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Posted: Tue Aug 5th, 2008 04:14 am |
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Larry,
Do we still need the gauge reading?
Jill
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eleent
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Posted: Tue Aug 5th, 2008 05:42 am |
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Hello: Progress Ghost flow through the heating side of the system appears to have been found. That's a piping problem which is not hard to fix. The pressure problem or unruly T&P has not yet been figured out. A gauge would be nice (essential) to see what's happening pressure-wise.
Yours, Larry
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shashalou
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Posted: Tue Aug 5th, 2008 04:39 pm |
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who knows what it looked like when it worked--2 plumbers have "fixed" it. the loop above the check acts as a heat trap, get rid of the check and let the pressure back toward the well. pipe size in an out of the tank has to be larger than the feeds to bath, heater and return, and the flex connectors I have seen are not the same as like pipe sizes.
the hot water will still cool when the pump turns on and the hot shower will still be affected by the deadband problem.
imo--and I'm not a professional
Last edited on Tue Aug 5th, 2008 04:47 pm by shashalou
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everlearning
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Posted: Thu Aug 7th, 2008 04:29 am |
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Water pressure gauge findings:
Static pressure 50psi
2 open taps of cold water 40psi
all taps, shut ...static 53psi
1 tap of hot water 48 psi
2 taps of hot water 43psi
all taps shut...static 53psi
done twice with identical results
i am told that our well water is gravity feed for my cottage.
The tank is way up the mountain/hill from where I am.
So do these numbers tell us anything/ something about why the T&P was going off ? or why the water heater was shutting itself off when set to High? (when the T&P was not going off)
jillLast edited on Thu Aug 7th, 2008 04:30 am by everlearning
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