Potterton Prima F40 gas boiler

BlackJAC · 23 Jul 2004

Having bled my radiators over the last couple of days, I now seem to have a problem with my boiler. When bleeding the radiators, I had the heating full on having been advised to do so by workmates.

While the water is still hot, it's only heating up to handwashing tempeture, rather than being hot enough to have a shower.

There's a noise (sounds like gushing sound) coming from a little grey box that has an automatic plastic switch. Once we switch the water heater off at the mains or by using the timer panel the noise cuts out and the switch on the small box moves. There are 2 of these boxes, 1 situated next to the boiler (the noisy one) and the other one that seems to have something to do with the heating.

Thanks

breezer · 23 Jul 2004

you have been ila advised, you should leed rads with system off.

have a look in your loft are both tanks full of water (i assume you have tanks)

BlackJAC · 23 Jul 2004

I've got a tank above the shower that has water in it, about 3/4 full and the other is a closed tank that's in the kitchen cupboard, so i'm not sure how I would find out if there was water in it.

ollski · 24 Jul 2004

The two boxes are motorized valves, one for the hot water and one for the heating. They simply open and close when a demand is made. The noise is the air rushing through them. You will find a vertical bit of pipe somewhere by your cylinder or water tanks normally with a fitting on the top to bleed the air from, this should be at a high point on the system.

Bleed your rads with the system off otherwise there is a chance that the hissing of air you hear is the pump sucking air in through the radiator bleed.

What is the temperature set to on the cylinder thermostat?

BlackJAC · 24 Jul 2004

There are pipes leading up from the left of the main water tank. Two of the pipes have red plastic attachments that presumably turn and one has a metal tap head attached. All of these attachments are fitted higher than the main water tank. Does it sound like one of these?

The gauge situated next to the boiler goes from 0-4 and there is a red needle just past the "1" and a black needle at 0. Is this the temperature gauge?

ollski · 24 Jul 2004

you have a sealed system, in that case it is very important that you dont start closing valves you don't fully understand. You need to locate your filling loop which may be by the cylinder or the boiler and is normally a braided hose with a tap at one end, open the tap on there and you will hear the water rush in, if the gauge is remote to you there get someone to watch it and tap the pipe when the gauge reaches 1 on the black needle to let you know to stop, bleed your rads with the system off and repeat the fill.
If you have been adjusting valves get someone in to check all is reset ok, when those cylinders explode in a steam explosion they take everything with them!!

breezer · 24 Jul 2004

ollski said:
when those cylinders explode in a steam explosion they take everything with them!!

i saw one being installed the other day,(actually it was a megaflow) so i asked the bloke had he ever seen one explode.

he said no, but the first ones quite often did, and on the training course they did show a video of one exploding he said the house was still standing, but it had no roof, where as previously it did, obviously he said if you had been in there at the time you wouldnt live to tell the tail

BlackJAC · 24 Jul 2004

I assume you aren't talking about the two motorised valves (the little grey boxes, as they reset themselves), and you're talking about those red tap valves that are stituated on the pipes? If it's the latter ones, I haven't touched them at all.

On my second fill do I bleed my rads until the black needle hits zero, or do I leave the needle at 1?

I'm sorry for asking what may seem obviuos questions, but I'd rather be safe in the knowledge that I'm doing it correctly and thus not ending up as part of the roof.

ollski · 24 Jul 2004

you need to fill it to 1 bar of pressure on the gauge, as you bleed the rads that will drop the pressure to zero so there will not even be enough pressure to push out the air, therefore you need to put the pressure back in to continue bleeding. Just keep on going round like this until all the rads have water and not air bleeding out.

It needs to be reset to 1 bar after you have finished. The grey boxes are not a safety component, the red ones probably are but best to touch nothing on a sealed system.

BlackJAC · 24 Jul 2004

The little blue tap that's next to the braided pipe isn't budging and don't want to start forcing it incase I can't close it off again. There's a brass like tap further up on the same pipe ( that you see outside for garden hoses) do I turn that one, or leave alone?

BlackJAC · 24 Jul 2004

Managed to turn the small plastic tap eventually. Got the black needle to 1 then bled all the rads till water came out each one, this happened more or less straight away with them all apart from the kitchen one where some air came out first. The black needle only went down just under a quarter and then I turned the plastic tap again until the pressure was back at 1. I put the heating/water heater back on and rather than it being a continuous gushing sound now, it seems to sound like a water and air gushing sound such as window wipers on a car make. Does that sound safe?

The kitchen rad now gives out a high pressure spray of water rather than just dripping out like the other rads.

BlackJAC · 26 Jul 2004

Rather than árse'n about with it anymore I've now made an appointment for a heating engineer to come and have a look at it on Friday. The pilot light is now not working

I'd like to thank the people that took the time to respond to my post.

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Potterton Prima F40 gas boiler

breezer

breezer

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