Re: Gurgling Boiler.

[Doctor Drivel]

Hi All

> > Setup is this: Gas Water heater in kitchen and hot water tank/heater > upstairs (a gledhill boilermate II). A fairly standard setup for a new > house, Id imagine. > > > On friday I came home to find water shooting out of my overflow (and a > leak inside caused by dodgy overflow plumbing - but that's another > story!). The ballcock in the top tank had split in half and was therefore > useless (one half was stoved in). Anyroad, I turned the water off, drained > the hotwater and credited myself with a smug feeling for fixing the job. > > I did notice that there was a unusual 'purring' sound coming from the > bottom of the boiler. > > Just now, that 'purring' sound has got much louder. On inspection, it's > water and air coming (more like spitting) from the bottom tank into the > top one via the 'expansion' pipe. I notice when I run the hot tap it goes > away, and when I turn the boiler switch off beside the boiler it goes away > too. > > Question is, what's going on? Could this be the cause of the broken > ballcock? How do I fix? has the boiler gone to boiler heaven? > > Thanks for any input. > > Colin

How old is the Boilermate? This is a thermal store. Is it square with a lift off front door? or is it round?

[Colin Chaplin]

Same age as house so 4 years old.

Round shape, no obvious doors on it to me..

[Doctor Drivel]

Do you mean a boiler on the wall?

Many new houses have thermal stores.

Is this the header tank on top of the Boilermate (thermal store)? They can be detached and fitted in the loft.

So boiling water is rising up the open vent from the thermal store cylinder into the attached expansion tank.

It sounds as if the thermal store cylinder stat has gone. It is usually set to 80C. Drawing off hot water cools the water in the store stopping the boiling.

From what you have described it appears nothing to do with the ballcock at all.

Terminology: Boiler: heats was and has a burner in it. Thermal Store: a cylinder that instantly heats cold mains water.

Try venting any pumps around the store and see what happens.

A point. It is about 4 years old. Drain the thermal store slightly, just below the header tank. Pour FOUR one litre can of Sentinel X-100 inhibitor in the header tank. Turn on the water. They should be re-dosed every 4 years, otherwise sludge may build up. And they take "Four" cans.

I would fit a Magnaclean filter on the CH return pipe to the store. A DIY job to clean and all the iron particles are collected in the filter. Well worth it. It is only 4 years old, so look after it.

[Colin Chaplin]

Yup

Yeah. To further avoid my clumsy descriptions I've posted a piccie

So boiling water is rising up the open vent from the thermal store

Yes.

That sounds plausible. What you are saying is there's nothing keeping the temperature constant, so it's just getting hotter then expanding into the header tank? (not that its a problem but did that soften/melt the ballcock !?)

If so, in my case I think it's a 'superloy 800' which Ive circled. This part is pretty cheap so almost worth a quick punt, how easy is the install?

Thanks for clarifying this for me :-)

Ive got what I think are two pumps.. cant see anything that would allow me to vent them?

Good advise, I think it I will follow it when I've got time off. I was shocked at the amount of muck in the bottom of the header tank.

... Thanks for your help, I am very grateful If I can offer any IT advise in return let me know :-) !!

Colin

[Doctor Drivel]

Yes.

Appears it did. You can fit a brass/copper float ball.

The 'superloy 800', is an electric immersion/stat. That is your backup if the gas boiler is down (the stat is inside the plastic cover). Is that the case? It appears you heat the Boilermate by gas, so this is not the stat that is defectrive. Look around the cylinder for the stat. There should be another one. I think it is the white knob in the cebntre. The time clock is at the top.

A stainless screw on the front.

Sometines the builders don't put enough inhibitor in the system and problems arise about 4 years later. The inhibitor is about £40 from Wickes and the likes - 4 cans.

I know everything about IT too. :-) I see yiu are pulling what looks like CAT 5 cables.

[Colin Chaplin]

Yes, it's heated by Gas.. I assume the immersion here is to keep things ticking over.

I've posted a piccie of the white knob as actually reading the text (what an idea!) reveals something interesting

's no comissioning peg in it, it looks like one *might* have been in the second right hole. The dial was up at full blast. Im following the instructions to see what happens...

Dammit, there goes any offerable knowledge I have ! Yes, that's the patch panels for all the cat5 throughout the house. The other end connects to my switch

Thanks again

Colin

[Doctor Drivel]

No. The immersion is purely backup if the boiler is down. Gledhill have the "Switch" auto electric backup. I'm, not sure if it was implemented on the Boilermate 2. The new Boilermates are very different to what you have.

It may be that the stats switching differential is widening. Turn it down and see what happens. If this cures it you still have a stat that is on the way out. But it last for many years like this.

[Colin Chaplin]

HMM. something is very odd then. If I turn the Superloy odd, gledhill starts rumbling as if its heading the water.

Actually there's definetly never been the peg inserted cos they are still taped to the top of it !

Turning it down seems to have helped - I haven't got enough confidence to leave it on when I'm out so it will have to wait to get a prolonged test.

What you are saying is that there's a (thermo) stat inside the gledhill, controlled by the dial on the outside, and you think this stat is out. But when it thinks the water is cooler than it should be, what is it using to heat the water up, if it's not the superloy 800?

Thanks again (and thanks to all who looked at the piccies on the website but too shy to post :-)

[Doctor Drivel]

Wheh you turn if "off" the water boils?

Typical builders.

Yep.

Maybe.

It switches in the gas boiler which heats the store. It switches in the pump (one of the pumps at the side) and boiler at the same time. There are two pumps. One pumps from the boiler to the store, and the other from the store to the rads; this pump is controlled by the room thermostat.

If turning down the thermostat stops the gurgling, then the stat is on its way out. Phone Gledhill and they will send you a new one. They are easy enough to fit, no drain downs or the likes.

[Colin Chaplin]

Ok. Despite reviewing my post before posting that's clearly nonsense (note to self: drink coffee before posting) IF I turn the Superloy on, the Gledhill starts heating the water (rumbling heating water sound). As soon as I turn it off, it stops rumbling and the water a few hours later water from the hot tap is cold.

Aha. Slowly the penny is dropping to how this all works. Give me a corrupt Exchange database anyday though :-)

From what you tell me, the water should stay warm as it'll be pumped through the gas boiler in the kitchen and back up. This isn't happening as the water in the tank is getting cold. Therefore, perhaps the boiler side that isn't working, or at least is another problem. Hence why the Superloy is kicking in and (perhaps) causing it's own problems.

I think I need to do a bit more testing over a period of time and figure out what the heck is going on.

Will report back!

[Doctor Drivel]

Look at for explanation:

Yours may be similar to the DIRECT MAINSFLOW TWIN PUMP