A gentleman from Hayling Island phoned to get a quote for a powerflush of his largish system. The usual problems; cold spots on rads, slow warm up times, etc.

When he mentioned that he has a Baxi 100HE a little warning light came on in my head. Initially, I was concerned that it may have an aluminium heat exchanger (acids a no-no). Fortunately, it’s policy that we always check out that any boiler we haven’t come across can be powerflushed. And there are hundreds – some common, some not so common. If we haven’t already worked on the precise version/model of a particular boiler we call the manufacturer’s tech support to make sure that we can use our usual choice of heating system cleaning chemical. Time consuming for us, but necessary.

Today, I was very glad our pre-checking system is rigorous.

Turns out the Baxi 100HE has a paddle-type flow switch than could be damaged by the instant reversing of water flow used by any competent powerflusher. And it’s not mentioned in their installer manual for the boiler.

The best wayto proceed is to isolate the boiler, make some temporary connections to the flow and return primary circuit, power flush and de-scale the rads and then re-instate the boiler. Dose with inhibitor and re-balance – of course.

After a quick call back to the customer to confirm what we had found and to confirm the best wat to proceed he was happy to give the go-ahead and we’re booked in to do the job next week.

Should be a nice one. Always pays to be prepared.