Hot water is on fire

CTH3

I always fill coffee cup with hot water in the morning to warm it up. Hot water came out of tap on fire today. Temp check showed 140+ degs out of tap. My super store temp set is less than that. Hot water has never come out steaming. System is Weil-McLain boiler and super store. 4 zone. 23 years old. Do I have a big problem? My well water pH is 8+. Zero hardness with high naturally high Na and Cl. Any thoughts would be helpful before I call a plumber on a Saturday.
Pics attached.

Jamie Hall

aquastat for your indirect may be faulty.

tim smith

Aquastat bad, flow check on dhw heating side pump stuck open. Pump contacts fused and pump stays on for indirect hw heater or if zone valve, stuck zone valve.

Karl Reynolds

That is not a Super-Stor indirect, that is a Triangle Tube indirect labeled by Weil Mc Lain. Those Thermostats are prone to failure, especially if they get water in the well under that black plastic cap. I don't know the W/M part number, but the Triangle part is P3KITTH-01 and it will work with your heater.

pecmsg

ASHRAE Recommends 140°F for 1 hour to kill the legionnaires bacteria.

Point of use should not be over 110°F to prevent scolding. Especially true for children and the elderly.

Agreed replace the temperature control and install a mixing valve on the outlet.

CTH3

Upon further review…..After some thinking, I’m not sure the problem is the thermostat. We have 3 heat zones and 1 hot water zone. We recently changed bedrooms from upstairs to down. We rarely had the heat on in the upstairs bedroom because we like a cool bedroom. Therefore we only ran 1 heat zone. We kept the downstairs bedroom heat always off because we didn’t use it. Now we are in it and have decided to turn heat on in downstairs bedroom for a few hours in the AM before we get up. So now there are 2 heat zones running in the AM. I think because there are now 2 heat zones running in the morning there is an extra push of boiler water into the superstore causing the hot water to be over temp set point even though the DHW zone pump isn’t running. Hope this makes sense to someone smarter than me. The second response by Tim mentioned a flow check. Would that mean a whole pump replacement if that is the likely problem? Attached is a close up of the DHW zone pump area.

hot_rod

If it has worked properly for 23 years, it is most likely a failed part, the aquastat is the first part to suspect. It can be checked with a meter, pull the sensor and heat and cool it to see if it responds.

mattmia2

I believe the device next to the circulator is a flow check.

HomerJSmith

Yes, Flow check. I think it is a failed flow check.You might try moving the adjustment knob. I would replace it with a spring check valve.

HomerJSmith

You can probably take the valve apart and look at the interior.

CTH3

Thanks for all the advice. I will check out both possibilities and let you know what I find. I think it is 70-30 for the flow check valve.

CTH3

Since turning off the heat in our downstairs bedroom I have not had hot water on fire. I did though install a CashAcme hot water mixing valve. Almost ran out of room for my upper bath hot water circulator because of the increased height of the output array. There is an auxiliary output on the tank but I couldn’t get the cap off and didn’t want to break anything trying.
If the WATTS check valve after the tank circulator is bad I’ll live with it. Thank you all for your help. e

Larry Weingarten

Hi, I know it's off topic, but it's a safety concern, so I'd like to draw attention the the relief valve on the tank. It's up on top of piping, and not really able to accurately sense the temperature of the tank. So, you basically have only a pressure relief valve. The tank is not protected from blowing up. Is there a way to move the valve so its temperature probe is actually sensing the heat in the tank?

Yours, Larry

HomerJSmith

ASHRAE Recommends 140°F for 1 hour to kill the legionnaires bacteria.

140 deg for 1hr kills grandma too.

CTH3

I just signed in to search for an answer to another question and saw Mr. Weingarten’s safety comment above regarding the pressure relief valve. As I said in my last post there is an auxiliary access on top of the tank but I couldn’t budge it. Is there a way to get it loose? If I could access it I would then put a pressure relief there.

leonz

Depending on how much room you have to maneuver around the plug a long breaker bar and a 12 point socket may work well. The one concern I have is whether this access is actually an anode rod.

pecmsg

HomerJSmith said:

ASHRAE Recommends 140°F for 1 hour to kill the legionnaires bacteria.

140 deg for 1hr kills grandma too.

You didnt copy the entire post

pecmsg said:

ASHRAE Recommends 140°F for 1 hour to kill the legionnaires bacteria.

Point of use should not be over 110°F to prevent scolding. Especially true for children and the elderly.

Agreed replace the temperature control and install a mixing valve on the outlet.

CTH3

leonz said:

Depending on how much room you have to maneuver around the plug a long breaker bar and a 12 point socket may work well. The one concern I have is whether this access is actually an anode rod.

As noted previously it is a TriangleTube branded by Weil-Milane. The access is labeled as “auxiliary” and it has a galvanized cap on it. In my mind that means no anode rod. Right or wrong?

HVACNUT

It looks to me like the T&P stem is in the path of the water flow. No need to change anything. 
Is that a mixing valve with the flex pipe or a crossover for the recirculating line?
And did you ever resolve the temperature override issue? Bad thermostat, right?

P.S. enough with the shark bites. 

dko

It is a mixing valve (cash acme tank booster), so the T&P is only measuring the mixed temperature - not the hottest temperature of the tank.

CTH3

HVACNUT said:

It looks to me like the T&P stem is in the path of the water flow. No need to change anything. 
Is that a mixing valve with the flex pipe or a crossover for the recirculating line?
And did you ever resolve the temperature override issue? Bad thermostat, right?

P.S. enough with the shark bites. 

I didn’t want to do any soldering.

CTH3

DKO: Sent my last message to quickly. No choice to edit sent messages either. Original temp problem has been solved with the mixer and adding the kitchen sink to the DHW circulator. There was no problem with the temp sensor/thermostat. We also turned down the bedroom thermostat.

dko

There are 3 dots at the top right corner of your post, if you click it you will see edit.

CTH3

DKO: Thank you

HVACNUT

Ah yes, it's sensing the mix. Duh.
Is there a return for the recirculating line? Can you pipe it like figure 2 and do the mixing valve downstream?

CTH3

I’m goin going to try and crank off the auxiliary cap first.  Also, will not take off original.  There are ones that have an 8 inch probe but that won’t reach the tank water either

mattmia2

You could put a tee at the connection to the tank, put a t&p valve with a long enough probe to get in to the tank in the run of the tee and build everything else off the branch of the tee(probably starting with an ell or street ell). There can not be any valve including the mixing valve between the t&p valve and the tank and the probe on the t&p valve must extend a certain distance in to the tank to sense the temp in the tank directly.

CTH3

A little struggle until I got the right leverage but the cap came off. New t & p with 8 inch probe installed. Thanks for all the help.