Hot water too hot

[Andyb01]

Hi All

Trying to get the bottom of a problem with my CH/HW. The problems started following the replacement of a defunct programmer (which we now know was wired in incorrectly and has been replaced with a Tempus 7). Have had both a CH electrician and now a plumber out a couple of times trying to trace the fault which is basically that with the HW only set to on the HW heats up to the temp set on the tank stat and then goes off - no problem. However when the CH comes on the HW also gets heated up (whether it is programmed to be on or off) and it just gets hotter and hotter overriding the tank stat and reaching temperatures with which you could make a passable brew! (probably around 70 degrees) not ideal with kids in the house! We have discovered that the motor on the diverter valve was shot (this has been replaced) and the plumber is now convinced that the diverter valve itself must be the problem and that it needs to be replaced as well.

Not that I don't believe him - he's a really good bloke actually - but just wondered if it could be anything else as we seem to have eliminated all other options.

Any assistance gratefully received.

Cheers

Andy

 

[twgas]

sounds like diverter to me.

 

[Andyb01]

sounds like diverter to me.

Thanks for that - I've been going nuts trying to solve this - once my man comes back and does the business I'll post to confirm a fix.

Cheers

Andy

 

[Softus]

sounds like diverter to me.

It doesn't matter what it sounds like, it hasn't been properly diagnosed.

You need to remove (with the power off) the powerhead from the 3-port valve, then run the system in CH only mode while manually holding the valve in the CH-only position - if the flow to the cylinder gets hot then you know the valve is closing the DHW port (port B), and if it doesn't then it's the powerhead and/or the wiring to it.