Replacement for Main Gas Multipoint Water Heater

One thing to check is the pilot burner. On one we had there was a very small path through the burner that passed the gas for the pilot. That used to become clogged with soot over time. Initially resulting in delayed ignition (with a corresponding percussive ignition), and then failure of the pilot.

The solution was to unscrew it, and then run a bit of 5A fuse wire through it to clean it.

(on the one I used to do you can get at the jet by displacing some of the main burner jet bars to either side of the pilot)

If it is the gas valve, then there are sources of reclaimed and reconditioned ones. Can you get a model or a GC number off it?

Not got any relevant recent experience with multipoints to comment.

Many thanks John, those are exactly the symptoms with percussive ignition, so I'll try to clean the burner.

ISTR it was a very fine hole - and you could normally see when it was clear if you held a good light behind it.

I've come across Morco gas water heaters from time to time. Might be worth a look-see?

Have you tried just blowing it through with compressed air?

John Rumm, spot on! The pilot hole was partially blocked so cleaned as you suggested and now the pilot flame actually reaches the thermocouple. I was on the verge of thinking of replacing the boiler because it had also started to trip the pilot (and then the main burners) midway through a shower, extremely annoying! Can only assume the turbulence caused by the main burners blew out the weak pilot. Anyway so far so good and thanks again.

Simon

Result! :-)

I think this is the mental version of "never throw stuff away - you never know when it might com in useful".

I think the "Main Severn 5" multipoint was retired about 35 years ago when my mum finally had CH installed - I remember coming home from college in the evening to a warm house for the first time ever!

Is this the big beast that used to be fitted on the wall above a bath ?. When I first left home the house of bedsits where I had a room had one of these.

It was open vented and sometimes when you tried to have a bath it took a couple of seconds for the burners to light and big woof of flame shot out of the hole at the front of the casing.

That sounds like an Ascot water heater (a.k.a. "geyser") - a much earlier (and more dangerous) device than the room sealed Main multipoints.

Generally called "gas geysers". I've never lived anywhere that had one, but, if it was downstairs and the bathroom upstairs, I've heard that people had to call up and down the stairs to get it to produce really hot water for the bath. You turned the water up to get a good flame, then gradually turned it down, stopping just as the flame started to die down. Of course, if the water stopped with the flame on, it could explode, so there was a safety cut-out which operated rather explosively; then I suppose you had to call a man out to reset it.

I briefly lived in a bedsitter that had a little one over the sink. This had no venting at all and had a water tap on the inlet.

No, this is a multipoint water heater in a similar form factor as a wall hung combi.

Sounds like what used to be called a "geyser"