No heating from an ecotech Plus 418 boiler

[AdamBrunt]

Hi all,

As above really.

Even when the timer is set to "ON" so we know it's not a problem with the timer.

The boiler has two thermostats on it (one for water currently 55c and one for heating - 70c ) which presumably lets us set the temp for both to get to - and not when they come on.

The boiler's display shows the current temp in the system ( 30c ). If I get the current status of the system the LCD on the boiler says "S.30" which means "Room thermostat 3/4 no heating demand"

There is no room thermostat anywhere in the house - just the two thermostats on the boiler and each radiator has it's own TRV (or whatever they are called) each of which is on and set high.

When the heating does come on - which is intemittently and bears no relation to the timer settings - a couple of radiators in the house (both in the extension and possibly the last 2 in the 'chain') don't come on at all but all the others do.

Anyone got any ideas as to what I might be missing ? A block in one of the two radiators that don't come on ? But then how does this 'feed back' to tell the boiler to switch off ?

TIA for any help.

Regards,

Adam Brunt[/b]

 

[mickyg]

the hot water control on your boiler serves no function, ignore it.
There is no demand to the boiler telling it to come on, so probably you have a fault with a motorised valve, possibly in your airing cupboard. This will be first thing to check. There's a million and one posts on here about motorised valves, how to check them etc. etc. Use search and ye will be informed

 

[AdamBrunt]

thanks for the relpy nickg, I thought it was unlikely to be a problem with the boiler itself.

IIRC we did have a problem with either the valve/diverter (in terms of diverter getting stuck in a certain position) before but I can't remember if we got it fixed.

Could it be that ?

 

[mrgas]

yes!

 

[AdamBrunt]

interestingly, without me doing anything, the boiler has just started up and the heating is coming on

I have literally touched/changed nothing - though the OH has pointed out that IF the timer had been on "timed settings" (it isn't - it is on constantly) then the timed settings are for heating from 3PM at the weekends.

EDIT: And half an hour later, the heating goes off again

 

[picasso]

The 3 port valve is probably stuck in mid position, when the hot water cylinder stat calls for heat the boiler fires up and you get heating, try turning the cylinder stat up and see if all the pipes on the 3 port get hot.

 

[AdamBrunt]

The 3 port valve is probably stuck in mid position, when the hot water cylinder stat calls for heat the boiler fires up and you get heating, try turning the cylinder stat up and see if all the pipes on the 3 port get hot.

Sorry picasso - most of that went over my head ... "3 port valve" ? and if the cylinder has a thermostat I've never seen it ??

 

[picasso]

View media item 27202
this is a fairly typical 3 port valve

View media item 28579
and this is a cylinder stat normally strapped to the side of the cylinder.

 

[AdamBrunt]

Ok, the stat on the cylinder seems to be set to 60. And without changing anything all 3 pipes into the the 3 port valve are very hot to the touch.

 

[picasso]

if all three pipes are hot are the radiators heating up ?

 

[AdamBrunt]

no - and the boilers not on either.

 

[picasso]

turn up the cylinder stat and see if the rads start to heat up.

 

[AdamBrunt]

turned the cylinder stat up to 80 and the boiler has immediately come back on.

Will the check the rads in a minute ...

All 3 upstairs rads (and towel rail) are on, only 2 (of the 6) downstairs one appear to be on - with 2 of the other 4 being stone cold.