Is an £800+ power flush the only option?

Cottage_Economy · 20 September 2017 at 2:49PM

We have an open system oil-fired boiler (fitted we think in 1998 when the house was built) with a hot water tank in the airing cupboard and cold water tanks in the loft. Separate honeywell zone valves each for hot water and heating. We moved in last year, had the boiler serviced last year and so far it has been trouble-free.

We turned the heating on Sunday and found that the odd radiator got warm but most were stone cold. I set the heating to come on morning and evening, and some radiator got a bit warm and others didn't. This morning one or two of the radiators were positively hot, but most were not. All the thermostatic valves were opened to maximum.

I was having the heating engineer in today to service the boiler (which passed as far as possible, clean as a whistle) and he checked the system. No radiators heated up at all after he switched the boiler to constant and turned up the thermostat. There is hot water from the tank to the pipe underneath the first radiator, but nothing is getting through. He took off the thermostatic valve on that radiator, checked it worked (which it did) but nothing was going through into the radiator. He also said the boiler is shutting off too quickly, and the pump is working fine but had been turned down too low so he turned it up to what it should be.

His view on the matter was the system was full of crud and needed a power flush, which would take two of them a full day and cost £600-£800 plus extra for an inhibitor and possibly a magnaclean. He also recommended the system be switched from an open to a closed to stop this happening again. Presumably for more money. I didn't go too far in finding out the cost.

Apart from the cost, I am concerned that pressure required to flush an unpressurised system plus switching to a closed pressurised system could cause leaks - most of the downstairs pipework is under tiles and I don't want to have them ripped up if something goes wrong.

Also being female, I would hate to think his suggested course of action to be the result of £££ flashing before his eyes.

Probably made the situation worse, but hubby and I have manually opened the heating valve to check whether that was at fault, and now we have hot radiators in all but the master bedroom upstairs (although the pipes to the radiator are finally getting hot in there after an hour) but nothing yet downstairs. While slow, we think it is making its way around the system. The lever on the valve is also slack across the whole length of travel (it wasn't before we depressed it), so presumably we've done something to that keeping it in the manual position (unless there is something manual we have to press to get it to go back?)

Valve is a Honeywell F3-9630 and we think is 'plumbed' in.

Alex1983 · 20 September 2017 at 3:00PM

Don’t convert it to a sealed system, you are asking for trouble, if it leaks you’ll have to have it all repiped.

Sounds like you should get the zone valve checked before you get it power flushed.

Wookey · 20 September 2017 at 3:08PM

If you's are capable take a rad of and drain it to see what state the water inside it is like. If there is no gunge present then stick the rad back on and add some fernox inhibitor into the header tank and then bleed the rad, don't worry if the water is black coming out of the rad, it's only if it contains sludge that you need to worry.

As your rads are now heating i think it's more likely to be stuck/seized valves which are common at this time of year as heating goes unused for 4-6 months and only gets noticed now when it gets colder approaching Autumn, maybe some balancing required and manually work the zone valves for a few mins so they operate freely.

Cottage_Economy · 20 September 2017 at 4:51PM

Wookey wrote: »

If you's are capable take a rad of and drain it to see what state the water inside it is like. If there is no gunge present then stick the rad back on and add some fernox inhibitor into the header tank and then bleed the rad, don't worry if the water is black coming out of the rad, it's only if it contains sludge that you need to worry.

I'll suggest this to my husband. The way the plumber presented it was there was no other solutions but to power flush.That's what made my nose twitch, there's always manual flushing.

Wookey wrote: »

As your rads are now heating i think it's more likely to be stuck/seized valves which are common at this time of year as heating goes unused for 4-6 months and only gets noticed now when it gets colder approaching Autumn, maybe some balancing required and manually work the zone valves for a few mins so they operate freely.

Well, a bit of an update. I can get the upstairs radiators almost fully working, but none of the downstairs. I have the tropics upstairs and Siberia downstairs. The thermostat, at the bottom of the stairs, is set to maximum and the boiler cuts in every now and then for about a minute or so, and then switches off.

Not a single pipe into the thermostatic valves is warm in any of the downstairs radiators, which would suggest something going on between the upstairs and downstairs.

Pump? He was adamant the pump was working and he had turned it up.
Sludge blockage? Can it be so cut and dried between upstairs and downstairs?
Can unbalanced radiators produce this effect?

Alex1983 · 20 September 2017 at 4:54PM

I’d turn all upstairs off and see if do stairs works, if not then possibly pump or blockage most likely around cold feed.

Cottage_Economy · 20 September 2017 at 4:56PM

Alex1983 wrote: »

Don’t convert it to a sealed system, you are asking for trouble, if it leaks you’ll have to have it all repiped.

Sounds like you should get the zone valve checked before you get it power flushed.

This is what frightens me. Don't have that kind of money to sort that out.

Cottage_Economy · 20 September 2017 at 4:57PM

Alex1983 wrote: »

I’d turn all upstairs off and see if do stairs works, if not then possibly pump or blockage most likely around cold feed.

Ok, will have a go and report back later to see what has happened.

theonlywayisup · 20 September 2017 at 8:20PM

multispammer wrote: »

Hi,

I'm a plumber in South East London and that does sound really steep for a days work..

Richard

Advertising your own business. What a great idea.

Two posts, two spams. Brilliant.

worried_jim · 20 September 2017 at 8:31PM

Spammer reported.

Warwick_Hunt · 20 September 2017 at 8:32PM

theonlywayisup wrote: »

Advertising your own business. What a great idea.

Two posts, two spams. Brilliant.

So why quote him?

Cottage_Economy · 21 September 2017 at 6:17AM

Ok, bit more of an update.

Only four of the smallest radiators got hot, none of the three large ones, and we could not figure out the order that things were coming in on either. Radiators on different sides of the house were heating up, when logic said it should be in order. I think the house was too warm for everything to heat up properly. In the end at 10pm I put the boiler programmer onto HW and CH twice a day to see what would happen this morning.

One hour after coming on this morning, all the radiators downstairs are now roaring hot. :T:T

So, presumably I now turn on the upstairs radiators and see if they all come on simultaneously tonight? I won't do it now, as the house is too warm and I think the thermostat will cause me to struggle like it did last night. I'll wait until tonight when the house is cooler.

After that I think I need to test the zone valve to make sure that comes on independently to the hot water. That is slack at the moment and I thought it should have some tension in the bottom two thirds of it?

Also, would it be a good idea to put some inhibitor in the tank in the loft anyway as a preventative measure? I know the previous owner had in the past - I've found some of it in one of the outhouses along with some kind of system cleaner?

Is an £800+ power flush the only option?

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