Old Ideal Vulcan RS55 on full pelt all the time

[Terrywookfit]

I would suggest that you find someone who is competent!!

This boiler is so basic that even my apprentice could fix it!

 

[doitall]

I would suggest that you find someone who is competent!!

This boiler is so basic that even my apprentice could fix it!

I thought the last plumber was the only one with any sense.

It can only be 2 things the thermostat or an motorized valve, sure the gas valve could be sticking but they normally fail safe in the closed position.

What hasn't been established is whether the pump still runs when everything is turned off.

 

[namsag]

He has said a couple of times that boiler stays on when power has been turned OFF and mentioned fuse spur,,
He even said he has to turn gas OFF
This takes every control out of what can be wrong and leaves a sticking gas valve..

 

[doitall]

Yes namsag I read that as well

Has the op tested the sparkie bits at the boiler to see if they are truly dead when everything is turned off or is he getting a back feed.

For example if the rads continue to get hotter and hotter it suggest the pump is still working as well, the boiler would also overheat if this was not the case even with gravity primary's

 

[namsag]

He tells us in his 4th line the pump turns OFF.

That the boiler stat OFF and switch on walll OFF and boiler is still ON

So unless both these are wired wrong which i doubt its gas valve and BASIC

 

[doitall]

As namsag I read that as well but has he tested it electrically to check there's no power to the boiler.

I have yet to see a gas valve stick on, ok it means nothing and I'm sure one of you guys will tell me different.

I must go dig the manual out I suppose

 

[hubie_27]

Well I may not always have known what is the correct info to give, gents, as I didn't know what all the buttons are called. Sorry for any confusion.

Terry: I do think the plumber can fix it - just didn't have the parts on Boxing Day, but he tested its safety and left me with hot water and warm house.

Some confusion may have arisen because at the first instance nothing would turn the boiler off except 1) the Gas Control Valve (on the boiler) and 2) the Mains Gas supply (on the meter).

After the pressure was turned down the symptoms changed and some control was restored. But it is still an issue, just now the room thermostat reached temp and therefore stopped the pump, but not the boiler.

Outside of the boiler the system works fine ie the pump works.

The problem is when the timer/control system turned off but the boiler didn't making a hell of a noise and steam in the loft.

Doitall: I'm not sure what the sparky bits are - manual ignition is a white clicker. The pilot light isn't terribly visible (but the boiler still lights).

 

[doitall]

In a gravity hot water pumped heating installation, only the cylinder stat controls the boiler, e.g. hot water off then so is the heating.

The programmer supply the power to the cylinder which in turn supplies the power for the boiler.

The heating side of the programmer supplies a feed to the room stat which in turn, turns the pump on/off but does not give a supply to the boiler.

There's is one more bit which overrides the programmer and that is a frost stat if fitted.

Have you tested for a 240v supply at the gas valve when everything is turned off

 

[hubie_27]

Doitall: Thanks. I get most of that (it always used to annoy me that the hot water took priority).

I have had the hot water cylinder stat down low so that the room stat would soon have priority once the

There's no frost stat.

The programmer does has separate hot water/heating controls – looks quite sophisticated but I think it post-dates the primitive system and I can't seem to get water/heating to run separately.

How do you test for 240v supply at the gas valve? I'm not qualified electric/gas but I can wield a multimeter, but I'm not going to dismantle anything.

I guess I just want to be able to ask the right questions when the guy comes back with the thermostat.

 

[doitall]

Turning the cylinder stat down will have no affect on the heating only by shutting the boiler down prematurely.

As I said assuming the wiring is as should be, the heating program only controls the pump, you cannot program heating only.

I have also assumed you don't have a honeywell c plan with a motorized valve as you haven't mentioned one.

You can test the electrics in the control box

 

[doitall]

Just got the manual up on the computer.

It looks like the cylinder stat has a satisfied terminal which will keep the pump and boiler going if the room stat is still calling.

The internal wiring is blue-neutral. Brown live to thermostat and Mauve is the live from the thermostat to the gas valve

 

[hubie_27]

Correct: cylinder stat takes priority, then when the water cylinder reaches temp the room stat is allowed to come in.

Thanks for the info on the wiring but I don't think I should meddle with the electrics - there are no coloured wires as such.

No motorized valve (I think) - 3 inch by 2 inch grey box by the water cylinder and pump - just a standard valve.

 

[doitall]

Get the guy to check the boiler stat when he turns up, as I said live in live out if calling.

I would check the sparkie bits before I changed anything, and it is dead easy.

Either you have power when the programmer is turned off or the gas valve has gone as previous posters have said

 

[namsag]

Out of every 100 failed gas valves i have changed 30/35 have been for letting by and staying on. But then part off my job used to be doing upto 15 gas leaks a day which this would come under.
It is very common and it can be intermitent

 

[hubie_27]

First prize to Namsag.

Fixed the boiler stat but the Gas Valve is still not operating properly - inconsistently sticking.

He's gone to pick one up.

H