Multiple tempering valves don't work

[Chesterton]

You eliminate 2 check valves and extra piping thats a good thing ! but he had a working system I dont see how that caused water to be at a 99 degree max . 150 degree water at the valve and 99 coming out makes me wonder if there is almost no flow at the valve . Assuming a good valve and equall pressure the water has to mix but if the hot line is plugged near the mixing valve maybe it would not reach the 120 setting or what ever you set it at also asuming its cranked all the way up

I could pull the valve, use the shutoff above it for the cold, and see what comes out? I'll have to think of a way to contain the water... but that's easier than redoing all the extra pipework.

There appear to be cleanouts at the y check valves. I could open those all up and make sure nothing is stuck as well.

 

[John Gayewski]

OK. The hot Webstone EXP E2 valve has a very slow drip at the main (yellow) shutoff. I was thinking about replacing that (although it appears that I have to buy the whole kit). In the absence of other ideas should I simplify the plumbing to this (see image)?

Another thought: Could there be air in the system somewhere causing trouble? I drained everything to solder the fittings for the new mixing valve (the old one was solder rather than union) and refilled with hot faucets open. At this point we've used hot water everywhere in the house...
View attachment 91052

You know something, that sounds very plausible there could be air. You need to have ball valves on this system at points that allow you to steer water through it. You need to bleed the air through the seperate paths to be sure it's all out.

 

[Sponsor]

 

[Fitter30]

Any y ( swing)check valves in the vertical may not work all the time need to be spring checks. Swing checks can hang open. Have any info on the emergency heat coil as for as gpm, pressure drop (head) ,brand and model of coil.Taco pump what model is it? Rinnai 94LSi at 130° temp rise is 2.6 gpm. Using a dhw heater for both heating and dhw can create some contaminated water from the heating coil if there no flow for long periods of time.

 

[Chesterton]

Any y ( swing)check valves in the vertical may not work all the time need to be spring checks. Swing checks can hang open. Have any info on the emergency heat coil as for as gpm, pressure drop (head) ,brand and model of coil.Taco pump what model is it? Rinnai 94LSi at 130° temp rise is 2.6 gpm. Using a dhw heater for both heating and dhw can create some contaminated water from the heating coil if there no flow for long periods of time.

It seems like 2.6 gpm is enough for what we’re doing.

Taco pump: 007-BF5. No info on the coil, but it definitely doesn’t get used for 7 months or so at a time.

 

[Jeff H Young]

There are no check valves between the w/h and the tempering valve on the hot and the temp is 150 at the valve So we know there is flow. furthermore youve got 99 degrees on the mixed side prooving both hot and cold are mixing and flowing, somehow there is too much cold passing through and not enough hot .
which check valve is airlocked or could be ? and how does 150 degree water wind up at the tempering valve?

 

[Jeff H Young]

I dont know if moving your check valve per honeywell instructions would help or an issue . but its not per plan

 

[Chesterton]

I dont know if moving your check valve per honeywell instructions would help or an issue . but its not per plan

Oh! I just put it where the old one was. Is there supposed to be more room between the mix and that first 90? I could see that causing a bit of a back pressure.

 

[Chesterton]

There are no check valves between the w/h and the tempering valve on the hot and the temp is 150 at the valve So we know there is flow. furthermore youve got 99 degrees on the mixed side prooving both hot and cold are mixing and flowing, somehow there is too much cold passing through and not enough hot .
which check valve is airlocked or could be ? and how does 150 degree water wind up at the tempering valve?

This is exactly what I am thinking. Maybe there’s some weird pressure that it is tricking it into thinking that it is mixing properly.

 

[Fitter30]

There are no check valves between the w/h and the tempering valve on the hot and the temp is 150 at the valve So we know there is flow. furthermore youve got 99 degrees on the mixed side prooving both hot and cold are mixing and flowing, somehow there is too much cold passing through and not enough hot .
which check valve is airlocked or could be ? and how does 150 degree water wind up at the tempering valve?

Set point for wh is 150° running commercial settings

 

[Chesterton]

OK. Thanks everyone for the help. My next steps: I'm going to measure pressure and flow rate on the mix side of the valve. Then I'm going to pull the valve and measure pressure and flow rate on the hot and cold sides. I'll report back when I have results (early next week).

Thanks again. Have a great Sunday!

 

[Fitter30]

Cut in two pressure taps at mix valve hot and cold lines. There can't be muiti valves that don't work. Over 30 lbs difference valve.stops working. Have you looked at cold water screen at heater supply?

 

[Jeff H Young]

My point was if we have 150 degrees all the way to the tempering valve and its coming out at 99 then hot water is clearly moving .
I think the check valve in the wrong location might cause the problem , maybe ? look at instructions

 

[Reach4]

Note that post #8 says inlet hot pipe (to mixing valve) is 150F, when measured with an IR thermometer.

 

[Jeff H Young]

equall pressure feeding the thermal mixer might be an issue

 

[Fitter30]

equall pressure feeding the thermal mixer might be an issue

Can be equal pressure. Cold goes straight in, hot goes through a check and the heater probably 5-8 lbs less.

 

[Jeff H Young]

Sorry I meant unequal pressure due to check valve at location it is causing pressure imballance compared to if it was in place recomende by manufacture . Im not seeing it as air but not disputing that theory either

 

[John Gayewski]

With no recirc line from the fixtures its not air.

 

[Jeff H Young]

Im down to my one theory , the closed system by placing check valve in wrong place (according to manufacture instruction) causing differant pressures at the mixing valve is all I have correction or we have 2 bad valves in a row I dont think so.

 

[Fitter30]

Take the temp on the check valve feeding the pump.

 

[Jeff H Young]

I see no mention of a domestic hot water recirculation system and the pump is reported to be for emergency back up heat . the pump should only run a minimal time to keep it from being a dead leg in system and no need for it to be hot except to keep the water safe from disease or freezing. all those temps or air in lines malfuctioning at 2 of the 3 check valves and the circ pump operation seems to matter not to the basic problem of water not hot enough downstream of the tempering valve .
Checking temp over at the check valve by the pump will be helpful how? Im assuming if its not an emergency the pump dosent run