Potterton Netaheat 10-16

[supervixen]

We've got an ancient old Potterton Netaheat 10-16 boiler. Apparently, BG tell us you can't get the parts any more.

We have it covered on a Britsh gas once a year service agreement although they won't cover the system because of it's age. They serviced it less than a month ago, and the following morning the tank started making a godawful noise.

It sounded like it was boiling the water. I fiddled with the boiler and noticed he'd turned it up from Min to Max. Turning it down reduced the noise although I could still hear something. My OH thought I was being neurotic so I didn't do anything.

Since then, I noticed the water getting hotter and hotter, in fact too hot to use. I've also noticed that all the time the timer is on (it's been on water only for ages) the boiler pilot keeprs firing up over and over again. It goes through a cycle, then stops and switches off for a couple of minutes...then fires up and goes through it again. The 'boiling' noise happens at the end of the cycle, just as it clicks back off.

The final straw was after last night. I turned the heating on, the radiators warmed up nicely, but then I turned the system back to water only because the radiators had got too hot, hotter than usual. This morning, despite being switched to water, they came on again, and what's more, turning the room thermostat right down makes no difference

I've called British Gas out and they'll charge us £132 for callout, and labour. But the parts are no longer available. And what's more, I'm scared after reading a plumbing/heating Q&A website that it's a boiler valve NOT the electrics.

CAN you still get parts for these? Im getting married in 2 months and we have NO spare cash for a boiler now. AND we want to move next spring! Can they be repaired?

 

[ollski]

parts availability is not full but most parts are available. If its covered on a boiler and controls contract you won't have to pay anything either. It sounds like the valve is passing which again I think is covered and can't see why you are being charged. Just tell them your boiler isn't working and let the engineer sort it, if he decides it is chargable he will tell you first.

 

[supervixen]

Thanks Ollski.

We're not covered under their insurance because BG refused to on the grounds that the boiler was too old and (they said) parts weren't available.

I suppose if they tell you that you can't get parts, you're more likely to agree to a new boiler!

Im glad I came on this site to find out otherwise. Cheers for that, you're a diamond.

 

[meldrew's_mate]

Did BG mechanic visit the airing cupboard? If so he/she may have shut the DHW cylinder balancing valve, and turned up the tank 'stat (it should be set around 60C Normally it is a 22mm gate valve on a pipe coming out of the bottom of the cylinder (not to be confused with ANY valves above 3' high). If si try opening it to about 1.5 turns from shut.

It's also worth checking your pump works and is unblocked, the increase in temperature could have finished it off if it is old. On this subject, stick your head up in the loft and check your header tank has some water in it and the ballcock works.

It also sounds like your 3 port valve may have stuck open (on central heating only), if it's a Honeywell the lever will be limp even with the hot water only on.

Finally, if most of this rings true you may benefit from flushing the system i.e drain and refill heating circuit until clear water runs to drain, then add flushing agent such as Sentinel Ferroquest or X400, redrain according to instructions and refill with corrosion inhibitor. Sounds complicated but not beyond a reasonable DIYer. I wouldn't recommend a power flush at this stage because of the expense and the age of your boiler.

 

[supervixen]

Thanks for all your help! I'm a bit of a girl when it comes to DIT but armed with this info at least I can tell the engineer where to look, and argue with him if he tells me the parts aren't available and I need a new one.