CH kicks in when HW is on

[werdas]

Hi, I believe I have Y gravity fed central heating system in my house

I had Honeywell evohome thermostat with few rad controllers =4 heating zones, and few rads not zoned- it does control my ch
but for hot water I use Sunvic Sunpro 2000 2 Channel 7 Day 5/2 Day 24Hr Programmer

so in the setting of programmer I always have CH always on and HW on a timer

All been working fine for couple or more years ,until I have my gas and electricity meters exchanged for smart ones,and since then I'm having problems, ( im not sure if it has anything to do you smart meters, but maybe they have burned something when they turned off electricity..)

so problems is/was :
1. I have noticed that there has been communication lost log message on Honeywell evohome thermostat every night.
2.my ch comes on when hot water is beeing heated, un-zoned rads gets hot if they re not turned off

however ch works and zones controlled without a problem

so contacted Honeywell for problem 1. which they said:

'The most common cause for loss of communication is that the BDR91 Wireless Relay Boxes are positioned too close together or next to metal items.

If it is fitted to your boiler, zone valve or Sundial valve, please make sure that you mount the relay on a non-metal surface and at least 30cm from your boiler or other wireless devices or metal objects.

Also, try to clear the fault log book by removing the batteries from the unit for a few seconds and then put them back in.

If the communication fault message appears again, check the installation of the relay box, reset it (press and hold the button on the relay box for 20 seconds) and rebind it to the evohome controller.

You could also try to move the controller closer to the relay box. '

So I have:
I have tried to remove batteries from the unit and putting them back- did not help
I did try to reset and rebind BDR91 Wireless Relay Box-No more communication loss but hot water still heats rads
I did not have structural changes since it was installed, so i believe it is not too close or too far away
plus I have only one BDR91 Wireless Relay Box, which is not fitted to the boiler,zone valve or Sundial valve

it is mounted on a dry wall and there are no other wireless devices close to it

I have also replaced my Sunvic Sunpro 2000 2 Channel 7 Day 5/2 Day 24Hr Programmer-with identical one-no difference

Im thinking of my next step to replace BDR91 Wireless Relay Box?
or could there be wiring problems?
3 point valve?
any advise?

 

[Echo the husky]

You need to diagnose the problem before replacing parts as that will soon get very expensive.

You say you have a 2 channel programmer where CH is left on so Evohome will work. In that case I would start by switching CH off on the programmer and just run the HW. If the radiators still heat up when heating the water that should rule out a fault with the Honeywell relay. The next place to look after that would be at the 3 port valve, for HW only the valve should not be powered and it should be held in the HW only position by the valves internal spring.

I assume the green light on the BDR is not lighting when you only want the HW on?

 

[werdas]

thank you for quick reply!!!!ok.turned ch off on the programmer and ran hw.rads still beeing heated.
the green light on bdr was not on.
so how do check 3 port valve?
thanks again

 

[Echo the husky]

It looks like you have a Dryaton valve, these have a small indicator which shows roughly what position the valve is in, it should be in the W position the same as the one in the photo:

Another test you can do here is to unplug the white 5 pin connector that feeds the valve that is currently strapped to the right of the cylinder thermostat and run the hot water only again. If the radiators are still getting hot either the valve or its motorised actuator are jammed.

The motor head can be removed by pressing in the black button that is currently between the valve and the wall and the head will come away from the valve. The now exposed brass spindle should be reasonably free to rotate, though it only rotates back and forth about 30-45 degrees. If it won't move at all the brass valve body will likely need replacement. If it does move freely it is likely the motorised actuator is jammed or broken internally, quite a common fault.

 

[werdas]

thanks again for a great support and help! here is the picture of the actuator and indicator position

I have unplugged the 5 pin connector and ran HW only, - still rads where getting worm, however I had that actuator removed from the valve.maybe I should have left it on the valve

I tried playing with actuator and rotate the black plastic lever and did see the inside rotated and was coming back to its position itself, at once it felt that it had been stuck but little fiddle and was ok, hope that makes sense

I think(not 100%) that when I tried to rotate the brass spindle, I could not with my hand.

So can I use pliers to rotate brass spindle?

Im away for a week so will follow further instructions and advise on my return, so brass valve body could be a culprit?
or shall I try new actuator?

also what actuator I have

Zone Replacement Valve Actuator Mid-Position Valve Actuator
or
Mid-Position Valve Actuator?

 

[jeff the gasman]

Faulty valve body or spring lug broken in actuator. Both common.

 

[werdas]

so worth replacing both i gues?

 

[Echo the husky]

Yes, especially if the brass bit doesn't turn easily, that model is not too expensive.

 

[jeff the gasman]

so worth replacing both i gues?

Buy a valve, replace actuator, if no better replace body and keep old actuator as a spare. Simples.

 

[werdas]

hello again
it all seems to be working now, perhaps after bit of fiddling it seems to work,so for now Im not replacing anything, but THANK YOU all, for great help