Zone valve wrong way?

tipperary

Hi all

I have noticed since our house was completed, that the upstairs radiators were heating up a bit, when the boiler was set to heat the hot water. The radiators were not as hot as if I set the boiler to heat the rads, but got quite hot nonetheless. When I raised this issue with the builder I was fobbed off with an excuse about the hot water rising to the rads, and not to worry about it. The builder has now gone out of business. We have a lot of insulation in the house, and do not use the central heating much to heat the house. The boiler is however set to heat the hot water cylinder daily (in conjunction with solar panels). As such, most of the time when the boiler is on, we would not be looking to heat the upstairs so we are wasting quite a bit of oil.

I was never comfortable with this, and have tried to get to the bottom of the problem. I removed the motors on the zone valves, to see if the valve was not fully closing, but all seemed to be fine.

It turns out that all three zone valves are fitted the wrong way around! As the system is currently set up, the valves are on the return pipework, and pointing in the wrong direction. From what I can figure out, I have two options
(a) drain the system down and refit the three valves the other direction, or
(b) drain the system down and try to swap over the flow and return pipes at the boiler side of the valves (not a lot of room available to do this).

The questions I have are:
1. Is the zone valve being fitted the wrong direction likely to result in water passing through a closed valve?
2. Does it make much difference if the zone valve is on the flow or return pipework?
3. Is there a practical alternative to draining the heating system to do this work? I have seen pipe freezing kits, but haven't used them and don't know much about them.

Any helpful advice appreciated.

aujopimur

Q1 No.
Q2 No.
Q3 I'd recommened a full draindown for any work that's likely to take time or where you might run into problems.

tipperary

aujopimur wrote: »

Q1 No.
Q2 No.

Thanks for that. Is there anything else that could be causing this heatloss? We are trying to get our system as efficient as practically possible, and it seems such a waste to be heating radiators in this weather just to have some hot water.

DGOBS

Sounds like you may have some reverse circulation, have the pipework checked for this when you next have a plumber in

anthonyos

i did an upgrade last week and used a two zone sunvic pack and the ch valve is passing when closed with dhw on replaced it today with new one and same thing after few min ch flow starts to heat up resulting in warm rads when dhw is on !!!i can blow threw the valve has anyone come across this in the past

JohnnieK

anthonyos wrote: »

i did an upgrade last week and used a two zone sunvic pack and the ch valve is passing when closed with dhw on replaced it today with new one and same thing after few min ch flow starts to heat up resulting in warm rads when dhw is on !!!i can blow threw the valve has anyone come across this in the past

After six and a half years my myson DHW valve has been passing slightly for over a year:o:o:o. I'm not setting a good example here:)

tipperary

DGOBS wrote: »

Sounds like you may have some reverse circulation, have the pipework checked for this when you next have a plumber in

I've just done a search on this, and it seems it can occur when the 'three tee' rule is not followed. I have attached a schematic of the pipe arrangement as it currently stands, and from what I can make out it breaches every single aspect of this rule:(

If the boiler connections were to be relocated as shown, should this eliminate the problem? I know I will need to get a plumber in to look at it, but want to make sure that what I get done will resolve the problem.

Thanks for all the help to date

shane0007

I would agree with DGOBS on this one, reverse circulation. Make sure the return from the rads is not teed between the return from the hot water and the boiler return. A common enough problem. Easy enough to sort.