CH/HW problem.....

[MANDATE]

Right the lever on the side!
This pushes against a lug on the quadrant so to speak. So if the valve was at CH only or mid position, the lever would be loose. But if the motor had been wound back by the reurn sping to the HW position then there would be resistance when you try to move the lever.
The purpose of this lever! well after draining down for whatever reason and with power off, you have to refill the system and to ensure water gets to both HW and CH sides you use the lever to hold the valve in the mid position. If you look carefully there is a latch in the slide so you can lock it in position. (unless of coarse you've broken it off like I did).

 

[DrEvil]

My parents have a v similar issue and I was going to post a new thread, but thought I'd jump on this one (not too sure what this forum etiquette prefers).

My parents have a Ravenheat boiler - listed as Primary Type A 'L51' and they have a hot water tank/storage system not combi.

The root of the problem is one of two things which is either that British Gas tinkered with something in the aering cupboard several years back or around the same time, they got a friend of a friend (who to be fair was a registered plumber) to install this system on the cheap several years back and subsequently got it corgi approved. They are often out the country over winter so didn't actually realise there was an issue with the system which, similar to the poster here, the central heating cuts out when the water is up to temperature. It will only come back on when the water temperature drops (takes couple of days) or if they drain the hot water. Other than that the system works fine.

They realised this last winter and called British Gas who wouldn't even look at it properly saying that they didn't install it and it was likely a electrical wiring issue and tried charging them a huuuuggge sum of money for the callout even though they have gas cover with them! So they are stuck and a bit old and frail so I wanted to look into this for them although I know not so much!

The first thing suggested here was a motorised valve. How do I check it out if it is this? My dad say's he has a Honeywell motorised valve and believes it's '1 way' (is this the same as 2 port?). Does this need changing to a 2 way one or something.

Again, v sorry for lack of knowledge/terminology and please let me know if I should be posting this in a new thread.

Thanks

 

[nickso]

I dont think the stat has mains isolation so coudn't that sensor potentially be at mains voltage ?

Tony

possibly, what of it?

 

[MANDATE]

Suggest you start a new thread and give details of motorised valve or valves.

 

[Golotus]

Right the lever on the side!
This pushes against a lug on the quadrant so to speak. So if the valve was at CH only or mid position, the lever would be loose. But if the motor had been wound back by the reurn sping to the HW position then there would be resistance when you try to move the lever.
The purpose of this lever! well after draining down for whatever reason and with power off, you have to refill the system and to ensure water gets to both HW and CH sides you use the lever to hold the valve in the mid position. If you look carefully there is a latch in the slide so you can lock it in position. (unless of coarse you've broken it off like I did).

thanks for that the latch you mention seems to be more about stopping the lever going into the manual position rather than something to hold it there

could the looseness of the lever be another indication that the unit is jamed up?

 

[MANDATE]

It's only when the motor/quadrant has been wound back by the return spring that the lever is restricted and not loose. If the quadrant has moved to mid position by the motor being powered, then it just leaves the lever lagging behind.
I believe your problem is valve related.
It's either not going to the CH position, or if you can prove it is then the second microswitch is likely to be at fault and this stops the boiler from lighting up.
You can remove the actuator head off the spindle (which should be easy to turn between finger and thumb) and try to see if you can get all three positions.