Welly's Boiler woes

[Welly]

Got home from Work last Friday night to the not uncommon 'Boiler Lockout' on our 11 year old Potterton Promax Condensing Boiler. No problem, I'll press reset and it'll re-start......no it won't.

I'm a HVAC engineer (without Gas Certification, I don't 'work on' boilers, I manage projects) but am knowledgeable enough after 25 years to find my way around a Domestic boiler and narrow-down faults. Anyhoo the boiler was trying to start; I had the fan running, pilot gas, but no spark being generated....then lock out (ignition failed, no flame sensed, back to square one).

Goes back to the yard to pick up 3 x electric heaters, switch on the immersion heater for Hot Water, and ponder the problem. Had a squint at the Ignition PCB and it looked like it'd run hot in a couple of places (failed components) but I re-soldered a previous fix on the board anyway......still no joy.

Saturday I order a reconditioned PCB for £30.00 + post + refundable deposit (when I return my old one).....being Saturday it'll get processed on Monday, I'll see it on Tuesday, the house is now down to 15 deg - this doesn't sound too bad but that's cold for the Missus......Sunday passes.....Kids start complaining......Monday comes.....complaints coming in thick and fast.....all eyes are on me! will this amateur* diagnosis be right? what if it's not? ....all eyes are on me.....Tuesday comes.....the day of reckoning.....the PCB arrives at my work...the suspense is tremendous.....I dart home in the afternoon to fit the thing....the house is cold and no-one's home.....gingerly I offer the PCB to the boiler (like presenting a gift)....please work.....please f*cking work.....connect the multi-plug and the "HT" lead.....

Carried out some checks* ......I'm ready......trembling I power up and 'call' for heat..........Fan runs.......Pilot Gas enabled.....Tick Tick of the ignition......Whoomph.....a FLAME......full Gas......Woo Hoo! Boiler running spot on

4 hours it took for the house to reach 19 deg, then later 21 as a 'treat'

I tell you though, I was shitting myself if that fix didn't work it would've been a new Boiler, more delays, and the weather's turning even more cold. In case you wondered, I don't have any Boiler Care packages, the reason being that I kinda work in that industry anyway and the Potterton is a twat to work on - many engineers won't touch them, if you open the combustion chamber cover you SHOULD replace all the seals @ £150.00 the whole thing is a piece of sh*t so you keep it running as best you can. It's being binned this Summer anyway.

[steve_earwig]

Why replace it, should be good for another 11 years now

Is there much else to go wrong on it? What I'd worry about is buying something even less reliable, from Sam's thread they're just as unreliable as all other household stuff, just enough to get them out of guarantee and *pop*, time to buy another one

Pilot light?

We don't need no stinking pilot light

[Welly]

The boiler is on its last legs, probably past it, like you say it's an 'appliance' modern fancy Boilers last about 8 to 10 years and become uneconomical to repair.

On mine the main burner is a fragile fabric/ceramic thing (£200.00) and is wayyy past its best (and will need those new seals I mentioned just to get to the thing) and the Aluminium heat exchanger (££££) is corroded (by the condensed water) so it's killing itself. A good condensing boiler will have a stainless steel heat exchanger, oh but they can crack.....

I could spend about £600.00 on the thing but a brand new Glow Worm is £650.00 and a much better investment.

[Bailes1992]

The other half has a Potterton Powermax boiler. It has it's hot water tank built into the boiler. Which as a result means when it goes wrong there isn't an immersion to switch on.
And Like you say when it goes wrong there is nobody who is willing to work on it!

The house I've just bought I thought there was a combi but apparently not. There's 15 year old boiler with a hot water tank. I'm kind of relieved about it. I can get a thicker jacket fitted to the hot water tank and an immersion heater. At least then if it goes wrong I can flick the immersion on!

[teamster1975]

Good result Welly!
We had a Wickes boiler at our last place and I had to replace the diaphragm in the DHW flow switch and the microswitch that triggered the CH. Very satisfying when you can fix them yourself! (No I would never touch the gas side )

[Welly]

Simple heating systems are definitely best IMO, I've got a Hot Water Cylinder heated by the Boiler or an Immersion and with a huge storage tank in the loft, we run 2 x power showers together and never run out of hot water. The Heating boiler is open vented with a Feed & Expansion tank in the loft, again as simple as possible.

Bailes - were you thinking of adding an Immersion heater to your cylinder? I tried doing that at my last 1960's house and split the copper cylinder it kinda folded in on itself when I was trying to unscrew the blanking plug [think: foot up against the wall and using full force] then everyone at work told me I shoulda heated the freds first and left the cylinder full of water to stabilise the shape of the copper vessel - at least just to crack open the plug, and then drain it down.

[Doggy]

Simple heating systems are definitely best IMO, I've got a Hot Water Cylinder heated by the Boiler or an Immersion and with a huge storage tank in the loft, we run 2 x power showers together and never run out of hot water. The Heating boiler is open vented with a Feed & Expansion tank in the loft, again as simple as possible.

I'm more or less with you there, 'cept I've got a non-condensing balanced flue boiler, (It was 2 years old, but had never been installed - £29 on eBay).
which I picked up the year after condensing boilers became effectively mandatory, so we 'installed' it the previous year.

I also have an inset multifuel boiler stove which runs almost exclusively on FOC waste wood. (So far this winter I've had to buy 2 bags of coal). We heat the house using the gas boiler/timeclock for the mornings and then run everything from afternoon till bedtime using the stove.

(In case your wondering, the stove circulates round the indirect coil in the HW tank by gravity, the gas boiler heats the water via an 'immersion blade' - water/water heat exchanger that screws in like an immersion heater. We had to solder in a second boss for the electric immersion heater.)

Well done sorting out the boiler. My one needed a gas valve about 5 years ago, then a year or two ago refused to light cause the HT cable to the ignition electrode was tracking to earth. Bit of high temp sleeving sorted that.

Gives you a nice, warm feeling.

[DaiRees]

Gives you a nice, warm feeling.

Haha, I see what you did there Doggy!

We've got a 17 year old Vaillant combi. Had a few issues over the years but generally it's been great. Saying no more on the subject, fate, tempting, etc....

[Bailes1992]

Simple heating systems are definitely best IMO, I've got a Hot Water Cylinder heated by the Boiler or an Immersion and with a huge storage tank in the loft, we run 2 x power showers together and never run out of hot water. The Heating boiler is open vented with a Feed & Expansion tank in the loft, again as simple as possible.

Bailes - were you thinking of adding an Immersion heater to your cylinder? I tried doing that at my last 1960's house and split the copper cylinder it kinda folded in on itself when I was trying to unscrew the blanking plug [think: foot up against the wall and using full force] then everyone at work told me I shoulda heated the freds first and left the cylinder full of water to stabilise the shape of the copper vessel - at least just to crack open the plug, and then drain it down.

What do you mean by a hot water tank and then a storage tank? I thought you just had one hot water tank that boiler heats and a tank above with a float that feeds the hot water tank?

I was planning on fitting a cold water tank in the attic to feed the electric shower, that way if anyone switches a tap on I won't be boiled to death like I am in my current house.

I don't want to touch my hot water tank, I only do 'lectrics. 'Lectrics are much safer ya' know! People have died in water. Therefore I was planning to get you down for free to fit my immersion heater? I knew you were a jolly good chap with an economical car who earns plenty of money so you wouldn't mind.

I also have an inset multifuel boiler stove which runs almost exclusively on FOC waste wood. (So far this winter I've had to buy 2 bags of coal). We heat the house using the gas boiler/timeclock for the mornings and then run everything from afternoon till bedtime using the stove.

(In case your wondering, the stove circulates round the indirect coil in the HW tank by gravity, the gas boiler heats the water via an 'immersion blade' - water/water heat exchanger that screws in like an immersion heater. We had to solder in a second boss for the electric immersion heater.)

Would love a setup like this. How well does the gravity fed system work?
Saying that, the house I've just bought doesn't have a chimney!

[Welly]

Vaillant are the best, the end. Well apart from maybe Viessmann (££££).

Worcester-Bosch aren't as good as they used to be (according to service people) whereas Glow Worm are regarded well, easy to work on and parts are cheap.

Bailes - I meant the Hot Water Cylinder has a Feed & Expansion Tank up in the loft, the Showers take their Cold water straight from the Tank so cannot be affected by toilet-flushing or sink tap opening etc. And I am fully booked until 2036, sorry

[trufflehunt]

My sister and brother-in-law live on a Scottish island, Arran. Last winter, with the storms and snow,
all the power was out for ages, and they discovered just how cold a house could be.

The instant the ferries were back on, they were off to the mainland for a hefty stove.

[steve_earwig]

Bailes - I meant the Hot Water Cylinder has a Feed & Expansion Tank up in the loft, the Showers take their Cold water straight from the Tank so cannot be affected by toilet-flushing or sink tap opening etc. And I am fully booked until 2036, sorry

Storage tank, cold water tank, tank with a float, expansion tank - it's a header tank I think if Sam just puts one in his loft he'll be a bit disappointed with the flow rate from the shower, unless he uses a power shower like what you does Welly. But then he'll have to make sure it's a) big enough to supply all the water he needs and b) not so big it ends up crashing through the ceiling...

The Croats don't believe in header tanks, heating is pressurised with a point next to the boiler to either drain it or put more pressure in the system, the hot water is mains fed as is the cold throughout the house, so no nasty things floating about in the header tank in the loft and bathroom water is always safe to drink (unless something nasty has got into it from the spring again...)

Incidentally, a few years back I got some thermostatickaly controlled shower mixer taps here, the one at my gaff works great but the one in my wife's house here long since went in the bin. Problem is the mains here is at about 6 bar (it's a long time since I looked but something like that anyway, enough to have the hose pipe do a dance and make holes in the ground) so it has a pressure regulator on it. Up at my house, which is further out of town, the pressure is tolerable without a regulator, but here it would be unacceptable to try and fill a glass of water and get soaked every time. I was trying to explain this to the plumber here, the regulator is basically a valve with a spring on it, once the pressure on the house side of the valve reaches the setting the valve shuts against the spring and only opens once the pressure drops again. What it doesn't take into account is the 80 litres in the electric HWT and the 90 in the wood burner. When water gets hot it expands, as the system is sealed by the regulator the extra pressure end stops the gauge at 10+ bar. It killed 3 of these shower mixers before I worked it out, the temperature is regulated by a bi-metal coil spring which is open to mains all the time and the cataclysmic water pressure was effectively crushing them to oblivion. He wouldn't have it though, even when I showed him pictures of the pressure meter on the regulator end-stopped What I'm actually meant to do is fit vents here and there, apparently it's quite acceptable to have them dripping all over the place

[lozz]

Potterton are a night mare,

There is a chap thats made a CD full of info on how to repair these and save money' (ebay iirc)
Most engineers will repair them,as theyve got a direct number to potterton,

Best thing to do with these is buy spare parts to put away ..good boilers but unrelible,ours never broke down in summer always winter,

[Bailes1992]

I don't fancy a power shower on an old fashioned boiler because of the cost to run it and inefficiency etc.

But I don't fancy a power shower on a combi either because if the boiler packs up you don't have a shower

[Welly]

Wiggy - don't you have any expansion vessels to take up the expanded warty pressure?

Bailes - you can't fit a Power Shower to a Combi Boiler, the shower pump will try to drag water through the Combi at a rate of knots and the boiler won't keep up, and the water pressure will also be too high (feeding the shower pump). Power Showers are designed to draw water from a storage vessel at equal-ish pressures, I have the showers with a built-in pump (look like an electric wall mounted shower) and they are very good, if a tad noisy, but they do need tank-fed Cold and via the Tank fed Hot.