Baffled by central heating with a mind of its own......ready to give up!!

[diamondgas]

Hi, I've not cleaned any filters as I'm not sure of what I'm doing. I have found the user manual for my boiler (heatline viso) on line which has all the parts identified but not sure what needs cleaning....any advice most welcome....I'll have a go at sketching the system

"Not sure of what you're doing" ... Get someone in who is, regards this filter, JoseGaf! It may well be where the problem lies and in my opinion needs eliminating before you remove radiators and rip up floorboards.

 

[JoseGaf]

"Not sure of what you're doing" ... Get someone in who is, regards this filter, JoseGaf! It may well be where the problem lies and in my opinion needs eliminating before you remove radiators and rip up floorboards.

when I say I don't know what I'm doing....I'm not a plumber or central heating engineer but have a mechanical engineeing degree and a reasonable appreciation of flow mechanics and electronics....I just don't know the ins and outs of boilers, thats why I've asked for help on here which has been really really useful........I've had 3 different central heating engineers round and not one has ever mentioned a filter (the guys who've come are able to change things but haven't been able to diagnose route cause)....I've downloaded the boiler manual and the description of how to clean the filter is pretty non-descript unfortunatley...I understand it is located near the heating return to the boiler but from memory it sits behind the pump so I imagine I either have to remove the pump or approach from underneath....if this is a job I'm not totally happy to undertake I just won't do it

 

[Millsy 82]

but have a mechanical engineeing degree and a reasonable appreciation of flow mechanics and electronics

Explain this please. If you have a pump trying to pump water around a heating system what will affect it? The more resistance that is on that circuit will prevent it from flowing correctly? So if your 6mtr head pump (as on most combis) is trying to circulate around an inadequately sized system it will dramatically reduce the effectiveness of the pump. If you put a new pump on a pristine system it may work for a while but not for long.

From what your posts have been saying I have read that this is an ongoing problem that you have been trying to sort through 3 different engineers? (I assume these have all been paid for what they have done) and you have been trying things to sort in the past? So I think you probably have spent longer and more trying to sort this problem than you say?

By all means keep flushing the system it's not going to do any harm but eventually you will end up having the pipework replaced.

If you can't afford 3-4k for a new boiler and heating system then don't have a new boiler and radiators just have the pipework redone then have the boiler and radiators replaced at a later date.

 

[Millsy 82]

As an example. I went out to a bungalow that had a whole new heating system installed 6 months earlier, it was a 5/6 rad system, all the rads took an age to heat up and some only worked every now and then, a quick look around and all the rads were shut off only allowing a very low flow through them, I opened a few up and water shot round them but the others wouldn't work at all, popped my head up in the loft and found that as soon as the flow and return entered the loft it was reduced to 15mm speed fit. I shot of and picked up a few 22 fittings and 2 6mtr lengths of speed fit and upgraded the flow and return, I filled up and turned the boiler on all the rads got red hot in 5-10 mins instead of getting Luke warm in 35-40 mins.

 

[JoseGaf]

As an example. I went out to a bungalow that had a whole new heating system installed 6 months earlier, it was a 5/6 rad system, all the rads took an age to heat up and some only worked every now and then, a quick look around and all the rads were shut off only allowing a very low flow through them, I opened a few up and water shot round them but the others wouldn't work at all, popped my head up in the loft and found that as soon as the flow and return entered the loft it was reduced to 15mm speed fit. I shot of and picked up a few 22 fittings and 2 6mtr lengths of speed fit and upgraded the flow and return, I filled up and turned the boiler on all the rads got red hot in 5-10 mins instead of getting Luke warm in 35-40 mins.

you are right, the system is rubbish and so is the boiler but its what I've got. In the last 4 years I have honestly spent less than £300 and that includes a new diverter valve which I fitted.....I do pay £15 a month for Eon boiler cover which arguably I'd still have if I had a new boiler.
The concept of knocking out my kitchen wall, a hole in my dining room wall and pulling up floorboards in all 3 bedrooms scares me....I have a 10mth old and a 2 1/2 yr old, the upheaval and having to re-decorate/plaster is something I just can't do at the moment....let alone probably afford.
There have been issues with the heating in the past but its now already better than its ever been....I'm waiting for my 'mates rate' engineer to fit me in as I want him to fit 22mm out of the boiler and as far as he can plus remove the unnecessary rad in the bathroom (closest to the boiler as theres already a towel rail in tandem)....these will both help.....

 

[diamondgas]

........I've had 3 different central heating engineers round and not one has ever mentioned a filter (the guys who've come are able to change things but haven't been able to diagnose route cause)....I've downloaded the boiler manual and the description of how to clean the filter is pretty non-descript unfortunatley...

I once re-charged a vizio and blocked the filter. They're quite easy to access and are eternal to the boiler, as I believe I mentioned before? Remind me/us please; is your heating system one pipe or two? And is it all in 15mm? I've seen a lot more than 6 rads ran of 15mm and heat no bother, by-the-way! You describe a primary restriction, by sounds of it if the temp diff between F&R are extreme?