Glow Worm 30sxi - hot water but no central heating.

The system has been used lightly since last October.

It fires up fine. It heats DHW but there is no central heating. What is the problem likely to be?

Reply to
Isfrizz
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Isfrizz wrote in news: snipped-for-privacy@googlegroups.com:

Have you checked the central heating pressure? It needs to be about 1.0 bar. If it falls to about 0.5 bar the lcd display flashes and the c/h won't come on. To fix it open the 'fill loop' (2 small 'taps' under the boiler body on my 30cx) until the display reads 1.0. Close the taps and the c/h should work.

HTH

TOJ.

Reply to
The Other John

Pump stuck? Valve stuck? deploy light weight hammer on any suspect devices.. grin. brian

Reply to
Brian Gaff

Stuck motorised zone valve.

Once you have it fixed, set the controls to put the heating on for 5 minutes once a week to save future problems building up over the summer.

Reply to
Bob Minchin

motorised valve..

Reply to
The Natural Philosopher

1.3 bar on the display. Has been raised to 1.7 bar, which it has been set to before.
Reply to
Isfrizz

Thank you for that - I will have a look (also, for BG's suggestion of mechanical persuasion, thanks).

I had thought "stuck pump", perhaps. The boiler used to make a lot of gurgling swishing noises, you see. Not now.

Reply to
fritbongwonkabwaki

If the boiler is of an age to be pressurised then it is unlikely to have gravity feed hot water so I concluded that it can't be a pump problem otherwise you would not have said DHW was working.

To check the pump, remove the central screw cover and have a rag ready to catch the drips and turn the shaft with a small screwdriver to check it is free. Switch on and see/feel that it is turning with the end of the screwdriver. Replace cover.

Reply to
Bob Minchin

I've done that with an old-fashioned pump. On this boiler, similar can be seen on:

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Page 43.

Reply to
Isfrizz

mmm. yerrs a combi dont use the pump for hot water do it?

hot pump a-hummin is stuck. cold pump and the silence of the lambs, and its all down to yer valves innit?

if the zone calve is calling for heat, there should be some sign, like a neon/LED on the boiler or something.

Reply to
The Natural Philosopher

Well, had a look at the thing. Manually operated zone valve (three pipes to). Pipes to rads warm or hot. Upstairs rads OK. Downstairs cold, or just above ambient, certainly not hot.

Reply to
Isfrizz

the Glow worm 30sxi is a system boiler as opposed to a combi boiler.

As its obviosuly heating hot water OK, we can rule out the boiler as a cause. This is because you have a 3 port valve or 2 off 2 port valves in the system somewhere along with a room thermostat and CH timer.

My money is on a faulty 3 port valve or on a faulty room thermostat or a faulty CH timer.

Put the thermostat on 30 degrees, put the timer to permanently on, and a green light should come on at the boiler. If it doesnt, then the 3 port valve is not opening and operating its internal microswitches in order to fire up the boiler.

Its either the motor or microswitches within the zone valves.

Reply to
Stephen

Ah ha....

you have a pump failure

The Hot water tank was being heated by gravity circulation as its higher in hieght than the boiler.

You mention the upstairs rads getting hot but the rads downstairs are cold..... thats because due to pump failure, the upstairs rads are heating by gravity and the downstairs doesnt as they are lower tahn the boiler.

You need to replace the circulating pump or at least free it.

Reply to
Stephen

Listening to the thing using a screwdriver indicates that it's going round. Changing the speed from I to II doesn't seem to change the note, though (but it only makes 200RPM difference).

Reply to
Isfrizz

I would expect to hear a change when changing speed setting. With the switch between contact positions positions I would also expect quiet.

Are you sure you aren't just hearing the 50Hz/100Hz from the pump magnetics, and in reality the pump is seized?

Reply to
Fredxx

Usually they do. They pump water round the primary circuit the same as normal, but a diversion valve directs the flow through the PHE rather than the rads.

Bit academic though since a sxi is a system boiler rather than a combi.

Reply to
John Rumm

My thoughts precisely.

There is an electromagnet in a motor. This will produce noise even if the shaft does not rotate.

The OP needs to remove the Big screw cap thats in the middle of the motor head, mark the shaft with a marker pen, then turn the heating on. It will be obvious then if the motor is siezed or not.

If there is a slot in the now exposed shaft, use a screwdriver to try and rotate it (with the power turned off of course) and see if the shaft rotates freely or is stuck.

If its stuck, new motor time. If it does rotate by hand, and still does not rotate when calling for heating, put a multimeter across the motor's terminals, there should be 230v on it. If there is, its new motor time.

If there is no 230v present when calling for heat, then there is a electrical problem elsewhere.

Stephen.

Reply to
Stephen

replying to Isfrizz, Lucylu55 wrote: No hot water but heating is on can you help

Reply to
Lucylu55

That was 2 years ago ffs.

Have you tried :-

a) reading the *date* of the post you are replying to. b) actually supplying some useful symptoms

Have you banged the hoover into the 3 way valve and knocked the switch that sets it to heat-only ?.

Reply to
Andrew

A bit more background information would be handy...

The 30 sxi is a system boiler rather than a combi I believe, is this true?

So what kind of water heating arrangement do you have? Normal vented cylinder, unvented cylinder, head bank, thermal store etc?

If the terms are unfamiliar, then look at:

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How is the system zoned and controlled?

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Reply to
John Rumm

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