Are heat exchange plates sealed systems & can't be clean

[woj101]

I have an Isar HE30 combi boiler that has deteriorated in its hot water performance over the last year. Had someone come to look at it this week - I said I suspected it was scaled up but he suggested the thermistor needed replacing.

He ordered one and came back 2 days later but it turned out it wasn't the thermistor. He's now ordered a new plat heat exchanger I think but hasn't returned when he said he would and we haven't heard from him.

I'll be getting someone else to sort it instead, but will it defo need replacing or can it be de-scaled in any way?

Thanks

 

[Paul Barker]

You could try puting Sentinel x800 into the system water. run system for two hours to distribute it evenly and clean out system then run bath on and off so it keeps switching back to heating to refresh the water with which it is cleaning the plate heat exchanger. perhaps during this proces the plate heat exchager will begin to work properly. Basically keep going until it does or until maximum time allowed for x800 is reached. I don't remember might be 4hrs.

Afterwards flush it all out really well a few times over including switching to hot water and back and to and back quite a few times to dilute it out of there, followed byt isnatlation of sentinel x100.

Chemicals quoted are simply one manufacturer's version there are others. But it is quite effective one and doesn't require neuralising, just quality flushing.


If that doesn't work you must pay someone competent and willing to remove and replace the plate heat exchanger and mess about like a school chemistry lab for an hour with chemicals with agitation and heat. Put chemical (x800 or chose your poison) into the two holes that are black poor normal boiled water into the holes that are white.

 

[woj101]

That sounds well worth a go, only problem being I know eff-all about the 'system' and wouldn't know where to pour any chemicals in.

Are there any guides for this sort of stuff?

Thanks very much.

 

[Agile]

Its quite easy to clean a plate HE but its rather messy.

You normally need a citric acid based product like Fernox DS40. However, unless you have skill in using it the results may not be so good on a DIY basis.

But if you dont know where to start its probably better to get a professional. Not all are prepared to clean the plate some will only replace it. Those who charge for the time taken will not give much saving.

We charge £136 in our local area to diagnose the fault and clean the HE if thats the cause.

Tony