No CH, HW OK. Y Plan system.

[MartyMalabu]

I did a number of checks after fitting the motor, including, starting with everything powered off and then calling just CH and observing the boiler light up and the radiators getting very very hot. Job done.

However, we have had a warm few days since Thursday and the CH has not been needed - until this afternoon, when her indoors complained there was no CH.

With the room stat turned up and just CH selected on the programmer the boiler was not getting called for. I went to the 3 port valve with the intention of moving the lever over to the mid position to get CH/HW manually just to warm the house, and as soon as I touched the level (hardly touched it at all in fact) it drove across and the CH came on.

My question is, what is the likely problem here. Is it likely to be a transient issue, or is there something more fundamentally wrong, like a sticking valve.

Your comments and advice is appreciated.

 

[matt1e]

s soon as I touched the level (hardly touched it at all in fact) it drove across and the CH came on.

My question is, what is the likely problem here. Is it likely to be a transient issue, or is there something more fundamentally wrong, like a sticking valve.

Your comments and advice is appreciated.

The valve is sticking or there's a contact problem with microswitch one

Matt

 

[MartyMalabu]

OK thanks. Unless the uswitch is likely to react to some WD40, it looks like I have a valve replacement to do.

I have done basic plumbing with compression joints & speedfit, so I am confident I can change the valve over. What I dont have a clue about are the steps needs to prepare the system for the change, and to recharge it afterwards.

Obviously first step is to isolate the power.
I have located the radiator with the drain point on.
I presume I have to find a stopcock in the attic which feeds a header tank and turn that off.

There is an isolator in between the pump and the valve - does this need to be turned off before I do anything?

Having done all that will the system just drain, or will I need to open any vents to let air in behind it?

After refitting the valve, what is the procedure for recharging?
Can I expect problems with air locks?
Do I need to add any additive to the header tank.

Sorry for so many questions, which must sound so basic.
Thanks.

 

[MartyMalabu]

Just to check.

Having replaced the motor and established CH was again working, it is now reluctant to move the valve over. If I call for just CH (as per the CH test with grey & white wired to 240v) the valve DOES NOT move.

If I move manually to about halfway, the valve then starts to move on its own. It cannot move between HW and midway.

The valve does not feel like it is sticking when I move it with the head off. Does this sound like S1 is knackered ???

If so is it replaceable ?

Thanks