No central heating but plenty of hot water

[duffbrewery]

Hello,

I posted the other day when i mentioned that i did not have any heating. the hot water is fine and i have bled all the rads (and replaced plugs with bledd valves cheers).

it seems to me to that the hot water is getting "lost in the system" between the bolier and the rads. one of the rads came on and last night, but just as soon as it did the hot water supply to it turned cold again. the boiler fires up and seems to be working (as i have very hot hot water in the taps????) but have random hot water in radiators. some mornings the rads in the b'room are luke warm to hot and then other days nothing. likewise with the radiator in the living room.

i have checked the motorised valves (honeywell v4043) and they work okay. i would have expected the pipe below the valve to be hot so it diverts to either heating or hot water but it isn't. when rads do come on the pipework in airing cupboard is too hot to touch but when there is no heating the pipes are cold. it is very random ??

i very confused
any ideas??

 

[gas4you]

You haven't given us any info on your system really, to go on.

I would check the pump has not stuck or is knackered first.

 

[duffbrewery]

i have a glowworm ultimate 80ff. which appears to feed standard type hot water cylinder and has small tank in loft with ballvalve. from the cylinder there is a grundfos pump and two v4043 honeywell motor valves.

cheers

 

[gas4you]

Also check the f&e tank is full of water.

When you bled the rads did you get water out of the upstairs ones?

 

[duffbrewery]

when i bled rads upstairs there was small amounts of water, and small amounts of air in one rad. what is f and e tank?? is that the one in the loft with the ball valve. if so, that does have water in it.

 

[duffbrewery]

don't think the pump is knackered as i have hot water to all radiators in the house at one time or another when i isolated each one after bleeding. seems to be that the hot water isn't getting as far as the pump to be pumped round the house. when we do get hot water in central heating system it never seems to last very long and ther is not enough to heat much more than 3 radiators.

 

[gas4you]

Have you checked for a bypass valve that is open fully instead of just 1/2 a turn?

 

[duffbrewery]

is that just the pump wheel type valve that comes down from the tank??

 

[Agile]

It can be anything but might be a gate valve with a red wheel top fitted between the flow and return pipes after the pump and before the two valves ( assuming the pump is in the flow! )

Tony

 

[D_Hailsham]

i have a glowworm ultimate 80ff. which appears to feed standard type hot water cylinder and has small tank in loft with ballvalve. from the cylinder there is a grundfos pump and two v4043 honeywell motor valves.

With two motorized valves it sound like an S Plan. However a photo would help any chance?

There is a diagram and wiring for S Plan at:

http://content.honeywell.com/uk/homes/systems.htm#S Plan

(Scroll down the page to see it)

One valve controls the boiler flow to the HW tank and the other to the rads.

The valve on the CH side may not be opening fully or the rubber ball which acts as the valve has swollen to impede the flow. Try opening the valve using the lever on the side to see if it makes any difference.

In your first post you said that the HW tank stat was set to 80C!! Have you turned this down to something more sensible e.g. 60C?

What temperature is the boiler set to?

If you do have an S Plan the Mfr instuctions say you need a bypass as both motor valves could be closed. It is NOT the valve on the pipe coming down from the tank.

 

[duffbrewery]

hello again,

i have checked various valves etc and the pump and water is now definately flowing as radiatior downstars heated up again, but only for a short time.

As i was puzzled i checked the hot water out pipe on the boiler and this was cold. does this mean my boiler isn't working. i have hot water but i think that is because it is heated in the cylinder by the immersion heater.