plate heat exchanger - keeping old system separate from new boilers

[Fishpond]

Hi

Need to replace an old 240k BTU boiler on an old house with old cast rads. Replacing with 2 new boilers and low loss header. It will be hard to get the old pipework and rads clean so I was thinking of using a plate heat exchanger to keep the old system water separate from the new boilers to avoid any risk of contamination or boiler damage.

Do plate heat exchangers work well for this kind of thing? Do they block up like a boiler would?

Any recommendations on which plate heat exchanger to get or where is best to get one?

Thanks.

 

[Roger Welton]

If you were converned about sludge I would steer clear of a plate-plate and maybe consider a tubular heat exchanger, to give a larger water passageways and less chance of blockages.

Have used similar(ish) systems in the past when there was risk of contamianating main boiler circuit, steam supplies to laundries, etc.

edit to add: I've used these chaps before now, they were very helpfull UK Exchangers Ltd - Heat Exchanger Specialists

 

[kozak1968]

Could you not use a magnetic filters to protect the boilers ?

 

[Fishpond]

Could you not use a magnetic filters to protect the boilers ?

Yes, always fit magnaboosters.... But given a powerflush is unlikely to get rid of all the crud, I was exploring if there were other options to help.

 

[chris watkins]

This is becoming a common practice (using plate exchanger) to protect new boiler plant, much easier to replace (possible clean) them than the boilers. I was talking to the main technical guy at Apha Boilers about these the other day if you need any advice.
If your LLH is large enough & in the vertical it will also work as a dirt separator.
Have you chosen your boilers, as some have larger water ways than others ??

 

[Fishpond]

This is becoming a common practice (using plate exchanger) to protect new boiler plant, much easier to replace (possible clean) them than the boilers. I was talking to the main technical guy at Apha Boilers about these the other day if you need any advice.
If your LLH is large enough & in the vertical it will also work as a dirt separator.
Have you chosen your boilers, as some have larger water ways than others ??

I've just noticed that Spirotech (the manufacturers of magnaboosters) do a LLH with built-in dirt separator - the Spirocross AX range see www.spirotech.co.uk/_media/en/brochures-producten-en/spirocross-ax_eng.pdf

I was planning on just using the LLH from the boiler manufacturer (probably Vaillant or Worcester Bosch) but has anyone had any experience of the Spirotech LLH?

 

[chris watkins]

I use these people, good & cheap. If you have the connections off-set & LLP is large enough it will do a similar job.
Headers

 

[Mike Jackson]

Look at using an Intergas boiler. They have 22mm copper water ways through the heat exchanger so are much less likely to suffer from blockages

 

[chris watkins]

Look at using an Intergas boiler. They have 22mm copper water ways through the heat exchanger so are much less likely to suffer from blockages

I picked Viessmman for the same reason after seeing EX at their HQ.

 

[Fishpond]

I use these people, good & cheap. If you have the connections off-set & LLP is large enough it will do a similar job.

Thanks, I need a couple of LLHs for different jobs now so I'll give them a call and see if they will help size them up for me. Hopefully this will be alot
cheaper than the spirotech or manufacturers options.

 

[Fishpond]

I picked Viessmman for the same reason after seeing EX at their HQ.

Yes,will need to talk to the customer about that. At the moment they only seem to want a Worcester or a vaillant. The history is that they've had bad experience with kestons before so now will only consider what they see as mainstream reputable boilers.