Boiler heat for water going to radiators

Yoda3

I hope someone can help us our 'emergency' plumber is stumped.

We have an 11 year old boiler, Vokera Linea 730. This year we had an extra red box expansion vessel fitted to the boiler and had to have the plate heat exchanger changed. We also were losing pressure slowly recently and put in some sealant (completely comaptible with system) and this fixed it. Our water in the system is clean and has good amounts of anti-rust stuff in it.

Our boiler went completely dead on Christmas Eve, no power at all. The fuse had blown on the circuit board(1.25a). The emergency plumber also found the switch on the wall supplying the power was faulty with live coming out on neutral and live even when it was switched off. The plug righted itself with a click, and we are waiting on an electrician to change the switch. However the switch may not be the real problem.

There was some water dripping out of the diverter valve, and prior to total failure the hot water in the shower had started to go a bit cold when it was meant to be hot. The fuse blew quickly after being replaced. The engineer left us with the heating on by 'sticking the pin' but no hot water, and we had to wait for a new diverter valve.

Diverter valve replaced but the water was going hot and cold, so he replaced the heat exchanger as well (ours was only 2 months old). However water still going hot and cold where the heat was going to the radiators not the hot water. He phoned Vokera who told him to strip down the diverter valve again.

It is still going hot and cold but he could not fix it so left saying he will send a more experienced engineer!

So now our symptoms are if you run the shower with high flow water the water runs cold and the heat goes into the radiators, if you run the shower on a low flow then the water stays a reasonable temperature and it can be used.

This happens even if the boiler is switched to hot water only.

Also bizzarely one of the radiators close to the boiler heats up through the return valve when the heat is being diverted from the hot water.

Anyone any ideas?

marlot

Was the whole diverter valve changed, or just the head?

I made that mistake on my system - and had to go back and change the whole valve.

Yoda3

There are three parts he ordered (left boxes behind - attuatore, 3 way valve overhaul kit and coperchio valvola 3 vie (seems to be in Italian!)

So guessing actuator, 3 way valve and 3 way valve overhaul kit

southcoastrgi

if he changed the valve why did he need the "overhaul" kit ? something doesn't stack up, if the heating flow pipe gets hot when you run the hot water I'd still be looking at the divertor as the first port of call

southcoastrgi

coperchio valvola 3 vie = cover 3-way valve

Yoda3

Well I just phoned the plumber headquarters, and now they have ordered another part - a service kit for diverter valve? The woman on the end of the hone does not have a clue, and every time a different engineer is sent out. Why if they replaced the diverter valve do they now think they need to service it?

Costing the insurance company a fortune and getting nowhere! After Monday we are back at work and I cannot take days off for this crowd to come round.

AVERAGEJOE_2

First step call a real heating engineer NOT a plumber.

Diverter valve or for this boiler hydraulic manifold and actuator head are only two replacement parts. the overhaul kit is to try repair your existing manifold.
This could be as simple as a faulty flow switch or ntc sensor.

Plus you say they ordered a service kit BUT that is what the original so called plumber already has there for you. (overhaul kit)

I run a heating parts merchants so come across these cowboys daily

Yoda3

I don't have much choice they are appointed by the insurance company

Seronera

Yoda3 wrote: »

I don't have much choice they are appointed by the insurance company

Well if they fail to fix it, then demand that they get Vokera out on a fixed price repair. You can only be messed about for so long.

I confess that when my own VokeraLinea plus did this a diverter overhaul kit sorted it..... But assuming they fitted it correctly there is something else going on with yours

bizzie

Not sure if this will help.
We've had a similar problem where when using hot water it never really got hot but the radiators did. We had the diverter valve replaced, and as it was still happening engineer kept looking and isolated shower upstairs. He believes the flowback protection has failed in the shower unit which allows mains cold to head for the boiler causing the problem.
Replacing shower soon is next on the list.

marleyboy

bizzie wrote: »

Not sure if this will help.
We've had a similar problem where when using hot water it never really got hot but the radiators did. We had the diverter valve replaced, and as it was still happening engineer kept looking and isolated shower upstairs. He believes the flowback protection has failed in the shower unit which allows mains cold to head for the boiler causing the problem.
Replacing shower soon is next on the list.

:money: