New Water Main Low Pressure At Hot Water Tap

[Dmac]

Hi,

I own a worcester, heatslave 15/19 combi oil fired boiler, now its never been fantastic at supplying gushing hot water to the bath tap, but we could live with it, my real problems began when i put in a new 25mm by 50 meter water mains pipe under the the garden, we never had great mains pressure, and i figured that this may be due to me having the old steel pipe mains supplying the house, Anyway after i put in the new main the water pressure coming into the house has increased significantly, i mean it fair blasts out of the cold water tap, my problem now is with my combi, believe it or not the flow to the hot water tap is now down to a trickle, i mean it takes 45 minutes to fill the bath and 5 minutes to fill a sink, could anybody give me some advice on how i could rectify this problem.

Thanks

Mac

 

[oilman]

It's almost certainly a scaled up plate heat exchanger (stainless steel thing that sits on top of the heat store under the boiler top cover) It's got 4 pipes connected to it.

Turn off the electricity supply to the boiler.
You will have to do without t water for a day.
Operate the pressure release valve to make sure the pressure is zero, then drain a few litres from the bottom of the boiler.
Disconnect the heat exchanger (The method is in the instruction book. Download a copy if you haven't got one.)
Get some acid descaler, you could use vinegar. Put it in the 15mm connections and mind the froth. If you can pump it through the connections so much the better.
Refit, refill, bleed and repressurise to about 0.8 bar.
Then fit a magnetic or electronic water conditioner to the cold water inlet pipe to reduce the scaling in future.

Have fun

 

[breezer]

erm, oilman, he can't do that since he is not CORGI registerd

 

[oilman]

Oh yes he can, it's an oil fired boiler

Apart from that, I have a question. Isn't ok to work on the WATER side of a gas boiler even if you're not registered?

 

[masona]

Oilman,

Are oil fired boiler common these days ?

Are they more reliable than gas boiler ?

What disavantage & advantage do they have ?

Are the oil fired boiler dearer to run etc ?

Can you get parts locally ?

TIA

 

[breezer]

My apologies oilman i assumed (wrongly) that corgi covered oil as well as gas.

 

[oilman]

Are oil fired boiler common these days ?

Very, everywhere there's no gas, and quite common where there is gas. Several UK manufacturers are making 20,000 plus of several models each year.

Are they more reliable than gas boiler ?

Probably, They have less complex control systems and are robustly built. Except combis of course.

What disavantage & advantage do they have ?

They are heavy, they need an oil tank, they benefit from regular servicing more so than gas boilers. If the servicing isn't done properly it costs oil. This is a difficult question for a short answer, but they can be worked on without being registered.

Are the oil fired boiler dearer to run etc ?

Slightly dearer than mains gas, but cheaper than anything else.

Can you get parts locally ?

I get parts from all over the place by mail order, but Plumbase, Plumbcentre, Jewsons etc. etc all supply parts

 

[masona]

Thanks for that,

What sort of size the average tank would be needed ? and I take it you can only get oil supply via road tanker plus need access as well ?

Sorry, Dmac I should've start a new topic

 

[oilman]

My apologies oilman i assumed (wrongly) that corgi covered oil as well as gas.

No need for apologies, the registration body for oil fired is OFTEC, see here .
There are lots of CORGI guys who think they can self certify installation of oil appliances as well as gas but THEY ARE WRONG. Building regs require OFTEC registration. Seperate certificates for pressure jet, vapourising, (seperate again for installation and commissioning), domestic tanks, commercial tanks,

 

[oilman]

Sorry, Dmac I should've start a new topic

Who cares? Thoughtful though.

What sort of size the average tank would be needed ? and I take it you can only get oil supply via road tanker plus need access as well ?

1200 litres is small, 1800 is better but when you get to 5000 litres you can get a good deal on prices, but you must have a bunded tank at this size.
Road tanker is normal, but I have a friend (Honest I really do...) who lives down a lane that's too narrow for a road tanker, so he gets it pumped to a 1000 litre tank on a trailer, then pumps it into the storage tank. All the people down the lane use the trailer/tank for their oil too.

 

[ChrisR]

Dmac if your problem is sudden then I'd have though a lump of cr*p is more likely than general scale which would build suddenly.

DS40 (mainly citric acid crystals) is about he best for a h/e. can be done static, better warm, needs a few changes of liquid.

I'm corgi reg My knowledge of oil is that you need nore when the level is getting down. Beyond that I look in a phone book, under OFTEC.