DIY Doctor

Hot water too hot!

Postby thespeedies » Sun Feb 08, 2009 5:25 pm

Our hot water from the hot water tank is ok when hot water only but with heating & hot water it's boiling hot. We have had a new thermostat fitted to the tank and a new directional control? valve fitted....both of which have not altered the temperature. Can anybody help please.
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Simply Build It

Postby rosebery » Sun Feb 08, 2009 9:17 pm

Yes get the guy that fitted them back and tell him to sort it out!
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Postby UserError » Sun Feb 08, 2009 9:30 pm

Sorry can't help but have the same problem.

I'm interested in any responses as I'd assumed I had muffed up the controls wiring, but maybe I didn't & this is something that happens occasionally.....

I am trying to get round to measuring pipe temperatures when the system is heating water and or radiators etc, to pin this down. My current excuse is that my thermocouple is looking a bit iffy & the temp readings I'm getting are nonsense.

Will report back if I find anything.
BTW, my system is a condensing boiler, two 2 port valves, programmable room stat and cylinder stat (this latter definitely makes the boiler fire up OK)

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Postby Steve the gas » Mon Feb 09, 2009 5:31 am

To both of you ........ turn your boiler stats down for the water or the system as a whole.

Steve the gas
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Postby UserError » Mon Feb 09, 2009 11:23 am

Steve the gas -
my boiler stat is on the "optimum" mark for condensing efficiency. I only turn it up if the weather's very cold (still on optimum in this weather). I can't measure the actual temp till I get a new thermocouple.

Is this setting likely to be 60deg C? This seems to be mentioned on the web a lot & appears to be the temp that DHW should be stored at? (this is way hotter than comfortable & causes cavitation in the shower pump)

Thespeedies. Apologies, don't mean to hijack your thread but maybe something useful will come out of it for either of us.
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Postby nitro23456 » Mon Feb 09, 2009 7:13 pm

You may need to balance the cylinder coil by adding a gate valve to the return allowing you to throttle back the hot water the same as balancing a radiator.
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