Any Boiler Experts?

[Cal_GTA]

We've got a vaillant ecotec 415 boiler http://www.vaillant.co.uk/stepone2/data/downloads/... which was installed in 2008 into a 70s house with original rads. We've not really used it for heating since we moved in earlier in the year as its been too hot. It seemed to heat the hot water just fine.

Anyway, we've recently had new thermostatic valves and two new rads + a powerflush of the system as it was really gunky, new thermostat as well. Old one located over a rad upstairs?! I get the impression the 08 installation had a 'minimal effort' air to it. I can't believe the system was cleaned back then either.

So now i've been trying to run the system to iron out any issues before its cold and not being familiar with normal operation i'm got some concerns.

- Heating set to constant

- Heating demand from thermostat. (set to max)

- Boiler fires for around 30 seconds. Then switches to 'anti cycling mode' which turns off the burner.

- It will remain in this mode for around 4 mins before starting the cycle again.

The rads are warm, but not scolding. Considering the thermostat is on max and its not winter it should be pretty baking downstairs after 3 hours, its not really.

When there is no heating demand the boiler will fire up and stay on constant during normal hot water heating time slots. I've not been in to test it yet, but i suspect that if there was heating demand during the normal hours of hot water heating, we would end up with the anti cycle mode as described above and luke warm water.

Any suggestions i get would be greatly appreciated. I can't believe this is normal operation. Our heating guys were happy to leave the system like this as the rads were getting warm. I'm not convinced.

thanks

Edited by Cal_GTA on Wednesday 14th September 11:19

Edited by Cal_GTA on Wednesday 14th September 11:21

[anonymous-user]

Is one rad a lot hotter than the rest?. If yes it could be acting as a bypass so will result in the boiler cycling. May be as simple as a 'rediator balancing' problem.

[Cal_GTA]

The first rad in line from the boiler is the hotest, (bathroom towel rail) but that would be normal wouldn't it? The people i had in said they were going to balance the system. I can't vouch if they did this or not as i was out.

We do have a new rad which is further away from the boiler than the one it replaces. could this make any difference to anything?

Presumably there is some sort of set up procedure that could be done on the boiler, as though it was being installed for the first time?

[anonymous-user]

I'm not an expert but it may be worth trying closing the bathroom rad valve in case it is acting as a bypass. Unless anybody else comes up with a better idea!

[Arthur Jackson]

Is the flow pipe exiting the boiler too hot to touch? If not then there's something amiss in the boiler, I'd say. If it IS, but the rads aren't getting hot check that the bypass valve on the system is correctly set.

[ss64ii]

I had a problem for 3 years, rads starting to not work one by one. Took all the thermostatic rad valves off and put normal ones on and flushed the rads out too, works a treat now.