Central heating radiators going cold downstairs when hot water put on.. Help!!

mikeluxy

Im not an expert on this....This was the Boiler that was recommended for our system....If, as you say there is a circulator in the boiler too do you think that the water from the new Wilo pump may be pushing the water round too fast and this may be causing problems....?

mikeluxy

Here is a direct link to our boiler....

http://www.viessmann.co.uk/en/products/gas_fired_condensing/vitodens_100-w_.html

keystone

Could you take two pictures please:

First the piping arrangements at the base of the boiler.

Secondly the area around the cylinder showing the circulator you replaced, zone valves etc. Host them on imageshack or similar and link to them here.

If the forum wont allow you to post links then just remove the http bit from the link before you submit your post. We an oput it back in again afterwards.

Cheers

Canucklehead

Hi,

You'll have a heat only boiler. Two 22mm pipes off the top left side.

Have you asked your installer for any advice?
You don't know if you have a Magnaclean or anything similar, what was in the quote ?
Or was the boiler fitted before you moved in?


GSR.

keystone

OK the reason I asked is that this boiler is normally installed with weather compensation. The page you linked to says that if weather compensation is fitted then the boiler must be installed as a 4 pipe system. That is to say heating and hot water are separate which is not as you have described earlier.

I agree with CH - time to call in your installer for a chat about it.

Cheers

frank.hopper

mikeluxy wrote: »

I have tried bleeding the radiators to no avail....I was wondering about a blockage but then again why would the radiators upstairs and downstairs get hot when the hot water is off...?

Mike

Probably because the HW circuit is not sludged up, unlike the heating circuit - less resistance in the pipework to the cylinder.


My previous post regarding backfill wasn't about air! it was using MAINS PRESSURE to dislodge the possibility of a build up of sludge in the primary pipework.

mikeluxy

Frank

Are there any risks associated with this backfilling idea or is it "like falling off a log"....I assume it would just be a case of connecting the hose to the lowest point and make sure pump and boiler are all shut down....?

Plus Zone valve set to manual...?

Mike

mikeluxy

keystone wrote: »

OK the reason I asked is that this boiler is normally installed with weather compensation. The page you linked to says that if weather compensation is fitted then the boiler must be installed as a 4 pipe system. That is to say heating and hot water are separate which is not as you have described earlier.

I agree with CH - time to call in your installer for a chat about it.

Cheers

Hi There

I have had a check and the link I sent was for a newer model of boiler...ours does not have the Weather Compensation fitted and its the standard 2 pipe system.

Mike

mikeluxy

frank.hopper wrote: »

Probably because the HW circuit is not sludged up, unlike the heating circuit - less resistance in the pipework to the cylinder.


My previous post regarding backfill wasn't about air! it was using MAINS PRESSURE to dislodge the possibility of a build up of sludge in the primary pipework.

Frank

Could you just explain the procedure you would use to do this...I think it may be worth a shot...

Basically just a hose connected to bottom drain valve...a friend sat in loft to keep an eye on expansion tank and me keeping one hand on the on off on the tap ?

Would you advise using low pressure first and gradually increasing pressure...?

I look forward to your comments

Cheers

Mike

keystone

Its not going to work. Backfilling only works on an EMPTY system and it won't shift any sludge anyway. Try it and watch the hose pop off the draincock in about 33 millisecs even with a jubilee clip in place. Oh and be prepared to hget very wet.

You really do need to get someone in to look at the system first hand and I would suggest the installer who installed your new boiler as a first stop. This has been going back and forth now for over 4 days and you are no closer to resolving the problem. Its costing you a small fortune in your own time.

Make that 'phone call.

Cheers

PS Thanks for info on the way your system is piped.