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Ask The Trades › DIY Forum › Plumbing Questions › Water too hot

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Water too hot (Read 15958 times)

Pineapple

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Re: Water too hot
Reply #17 - Sep 24^th, 2011, 11:23am

CWatters wrote on Sep 24^th, 2011, 9:51am:

Quote:

Turning it right down makes the boiler go off and right up makes it go on...

If it really is controlling the boiler (and the central heating is off) it's hard to see what could account for the water getting too hot. However, normally you only have to turn the dial a few degrees for it to click and the boiler fire up or shut down. If it only controls the boiler when you turn it all the way up/down then I agree worth trying another stat.

One problem with hot water systems is that 60C is hot enough to burn a child but if you turn it down there is a risk of Legionaires disease. I did wonder if somone had just turned the stat up. eg perhaps it set to say 50C before and someone turned it up or knocked it? Sorry if thats a rather obvious suggestion.

I'm beginning to think it's all in my mind Roll Eyes

« Last Edit: Sep 24^th, 2011, 11:24am by Pineapple »

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Re: Water too hot
Reply #18 - Sep 24^th, 2011, 12:05pm

When the hot water (HWS) is off, there should be resistance on the manual slider on the end of the MV, when the HWS is calling there should be no resistance.

Go through the program.

Turn the HWS on on the programmer.
The boiler and pump should run provided the cylinder stat is calling.
Turn the stat down and the boiler should stop, the pump may run on for a few minutes or so.

Now turn the HWS off and the HTG on, check whether the pipe going to the cylinder still gets hot.

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Pineapple GDPR opt-out Total Thanks: 147 For This Post: 0	Re: Water too hot Reply #19 - Sep 24^th, 2011, 12:50pm Many thanks...will do. Update...the supply pipe stayed cool when the c/h was turned on.
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Pineapple GDPR opt-out Total Thanks: 147 For This Post: 0	Re: Water too hot Reply #20 - Sep 25^th, 2011, 10:34am I guess that the valve is working as it should.
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thescruff Global Moderator Trade Member Author Offline Who said plumbing was easy. Posts: 6037 Total Thanks: 147 For This Post: 0 Gender: Trade: Plumber	Re: Water too hot Reply #21 - Sep 25^th, 2011, 10:54am You supposed to post the results of the tests.
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Pineapple GDPR opt-out Total Thanks: 147 For This Post: 0	Re: Water too hot Reply #22 - Sep 25^th, 2011, 10:58am thescruff wrote on Sep 25^th, 2011, 10:54am: You supposed to post the results of the tests. From earlier post: Update...the supply pipe stayed cool when the c/h was turned on.
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thescruff Global Moderator Trade Member Author Offline Who said plumbing was easy. Posts: 6037 Total Thanks: 147 For This Post: 0 Gender: Trade: Plumber	Re: Water too hot Reply #23 - Sep 25^th, 2011, 11:56am That's good news. What have you got the boiler stat set at, try turning it down.
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Pineapple GDPR opt-out Total Thanks: 147 For This Post: 0	Re: Water too hot Reply #24 - Sep 25^th, 2011, 1:54pm The boiler stat is at 4. For info, that governs just the c/h, yes?
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thescruff Global Moderator Trade Member Author Offline Who said plumbing was easy. Posts: 6037 Total Thanks: 147 For This Post: 0 Gender: Trade: Plumber	Re: Water too hot Reply #25 - Sep 25^th, 2011, 1:56pm Quote: The boiler stat is at 4. For info, that governs just the c/h, yes? No the boiler stat is both. The room stat controls the htg
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Pineapple GDPR opt-out Total Thanks: 147 For This Post: 0	Re: Water too hot Reply #26 - Sep 25^th, 2011, 2:20pm Showing my ignorance again, why would you have the boiler stat and the cylinder stat both controlling the water temp in the h/w cylinder?
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greg

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Re: Water too hot
Reply #27 - Sep 25^th, 2011, 4:37pm

The cylinder stat controls the temperature of the water stored in the cylinder, the boiler stat controls the temperature of the water passing through the boiler.

If you had your cylinder stat set to 60deg and your boiler stat set to 50deg, then your cylinder stat would never be satisfied as the max temp the water in the cylinder would reach would be 50deg.

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CWatters Super Member Offline "Daddy fick it" says James Posts: 5150 Total Thanks: 58 For This Post: 0 Gender:	Re: Water too hot Reply #28 - Sep 25^th, 2011, 7:15pm I think it's time to actually measure the temperature of water coming out of the taps with a thermometer Another crazy thought.... Has someone left the immersion heater on by mistake?
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Re: Water too hot
Reply #29 - Sep 25^th, 2011, 8:46pm

CWatters wrote on Sep 25^th, 2011, 7:15pm:

I think it's time to actually measure the temperature of water coming out of the taps with a thermometer

Another crazy thought.... Has someone left the immersion heater on by mistake?

I can't find a thermometer that measures above 50c. The immersion heater has a socket with a light that comes on when drawing power.

I've now turned the boiler stat down to three, which is probably more of a summer setting.

« Last Edit: Sep 25^th, 2011, 8:48pm by Pineapple »

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