Shower temp
I just replaced my mixing valve because my shower went from scalding to lukewarm warm in 10 minutes They are all pressurtrol set to the highest setting. I have 160 Gallons of supply so that is not an issue. The boiler is set at 160 hold and the indirects are set at 140 the mixing valve is set to 125 but none of the showers in my building will get over 110, the sinks are 125. What is going on?
Comments
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Mixing valve may not have been the issue, unless this was happening everywhere.
What type of shower valves? If it is a single handle valve, and Im guessing it is, and only happening in the showers, there is either a mixing valve dedicated strictly to the showers gone bad or the spindle(s) (generic name) is going bad in each of the shower valves. What is the brand name of the shower valves that don't get hot. They could also be out of adjustment too.
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Shower valves have various anti-scald features, which may include thermostatic elements and limit stops that restrict how much hot water can be mixed with cold. The elements can fail and need replacement. The limit stop adjustment depends on a consistent hot water temperature from the pipes.
Why would anyone want a shower over 110°F? Anything hotter risks scalding.
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Bburd
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Hi, You may also have a recirculation line and when hot water is used, it can pull cool water backwards, through the line. Have a look (and feel) and make sure the check valve that should be in the line is preventing backflow. Also, this could be a mix of problems with the shower/s and recirc line at higher gpm.
Yours, Larry
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My question is that the shower starts out at 120-3 in all 8 units and gradually drops to 110 at max output over 10 minutes. Shouldn't the mixing valve and shower limiters keep the max water consistent? They are all Symmons treptrol units.
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yes
They have to be set up correctly!
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Symmons temp trol. Probably 96series but could be 100series type shower valves. How old are they and when was the last time they were rebuilt. Symmons shower valves take a repair better then most.
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Question? Do they also fluctuate from cold to hot?
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the Wife does!
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Lol.. but seriously. If you put your hand under the shower and feel it go from warm to cold to worm to cold the spindle in the shower valve is no longer working properly and needs to be replaced.
I have rebuilt numerous full locker room shower valves all at one time because they all would show some level of hunting for a temperature.
A Symmons T-10 and TA-4 parts are what would be needed and are a very reliable fix and relatively easy to change. These part numbers are for a 96 series valve.
The 100 series have different part numbers.
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It starts out at 118 with the handle at 3/4 and after about 10 minutes it drops to 108 fully open. They are series 96, I rebuilt mine two months ago trying to rule that out with no change.
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Have you checked the hot water temperature at a nearby sink while this happens in the shower? The problem may originate at the water heater.
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Bburd0 -
The water out of the sinks is between 123 and 125.
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I have 2 indirect hot water tanks which put out water at 140 heated by the boiler, steam, set to hold at 160.
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If the delivery temperature from the mixing valve at the water heater is 125F and the temperature of the water coming out of the shower head drops to 110F, the shower valve is the problem. UNLESS there’s a cross connection somewhere.
8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour
Two btu per sq ft for degree difference for a slab2 -
The Symmons Temptrols are pressure balancing to avoid scalding if someone flushes a toilet (for instance), but are otherwise passive with regards to temperature. If the piston is free floating, it's fine.
The Symmons do have a built in adjustable stop (for back in the day when people didn't use active mixing valves) to limit absolute temp.
If the mixing valve output temperature stays at 125 while the showers don't reach that, you can try to adjust the limiting set screw.
Why you're getting fluctuations is something I don't know. A couple of people suggested cross contamination hot to cold, and something like a single handle kitchen fixture can even do this.
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then it's the shower body!
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Does water temperature fluctuate out of the sink hot faucets? Are they single handle type? How many single handle faucets in the building? Cartridges in single handle faucets can be a cause of H&C crossover.
Any Y hose connectors, on laundry sinks for example? Possibly someone in one of the 8 units connected an appliance causing a cross over?
@Larry Weingarten asked about a HW recirculation system, do you have that?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream
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Wow that's a far reaching but not out of the question thought.
If you only change the spindle and not the seats, if the gasket is doubled up on the T-12. If the adjustment screw on the spindle (TA-10) is in the wrong place these issues can occur.
And at times I have found that even when the spindle can rattle when shaken, it can still be bad and need replacing.
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Almost all of our faucets are single handles but they stay constant at 123-125 it is only the showers that loose temp over 15 minutes. We have a combination of Symons Delta and Moens shower valves that all start at 123 at 3/4 and drop down to 108 fully open after 15 minutes. It doesn't make any sense.
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@pecmsg I would agree with you about the body but it is the same in 8 units with three different valve brands. This is what the mixing valve looked like when they took it out.
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is there a central mix valve back at the HW tanks?
If this is a rental property having a central mixer set to 120 is a good idea for scald issues, if the tanks are running 140f or so?
Either way a ASSE 1016 shower valve needs to be +or minus 3 degrees accuracy up to 5 gpm flow
+or- 5 degrees over 5 gpm per the listing criteria .
Still wondering about a recirc loop?
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
theI&O manual indicates the valve needs 45 psi and 1.5 gpm flow to balance properly.
Could there be a plugged strainer on a main line PRV causing a pressure drop? A gauge at the tank would show you if pressure is fluctuating
Also the H&C pressure needs to be the same, sometimes the hw pressure increases if there is not a thermal expansion tank, as the shower flows, pressures stabilize and the piston inside shifts to accommodate
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0 -
@hot_rod I just posted pictures of the mixing valve that was removed. The pressure is the same on both sides of the system. It was clogged with calcium but the new mixing valve next to the tanks didn't change the temp drop. Again not a supply issue we have 2 80 Gallon indirect tanks with the boiler set at 160, all temps confirmed.
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I doubt it's your issue but since it was so odd I want to share it again
My sister and her family kept having issues where sometimes they would have hot water for a shower but usually not. Just like yours it would start hot and then cool off.
They have touchless faucets on two sinks and their plumber didn't install the check valves so water was going from the cold line into the hot line. Because the faucet is always in whatever position they leave it in, the touchless part comes after that.
Just throwing it out there as an odd possibility.
Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.
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Another example of cold to hot crossover. Suspect that is the issue for @gfrbrookline . The shower is strong enough flow to activate the crossover... But the faucets are not?
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Helpful site on how to check for Crossover
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I just replaced the mixing valve it had a lot of crust build up inside it. The issue is much better but it is still there.
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You have different types of shower valves. They all seem to be performing differently.
The thing to do is check each shower and take careful note which ones are performing properly and which ones are not.
The problems you have are at the water source, at the shower valve, and at each type of shower valve.
If they are all pressure balancing shower valves, but are different brands, each shower will need to be dealt with individually.
Here's a tip. Each shower, if truly a pressure balanced shower valve is in essence, its own mixing valve.
If the cartridge on each of those shower valves are like the mixing valve pictured, your work is not done yet.
You will need to investigate each valve and repair/rebuild as required.
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If a mixing valve at the HW tank was corroded like that it can stick the spool and temperature will be very erratic, hot, warm, cool etc. Cleaning and rebuilding the 3 way mix valve may solve the problem.
Bob "hot rod" Rohr
trainer for Caleffi NA
Living the hydronic dream0
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