Has anyone heard of a plate flush?

[kron77]

Hi there. Ecodan 11.5 kw and 3 years old. Mitsubishi service technician came out and noted low flow. He isolated the ashp and it was achieving 20l. When not isolated it’s reporting max 2l. Normal is above 5 I think. System was warning LP and a few times it went to L9 when on dhw. 
 

so here’s the thing. Service guy is saying the solution is a plate flush because apparently it’s clogged with gunk cause the system was not installed correctly by the installer. 
 

I fell off my seat when they quoted £1200 for a plate flush, drain system, add anti freeze (which was not done originally). 
 

anyone seen this before? And I getting my pants pulled down here? 

[Onoff]

https://renewableheatinghub.co.uk/forums/renewable-heating-air-source-heap-pumps-ashps/flushing-an-ashp-system-and-ufh-questions

[sharpener]

Sound like you are being taken for a ride.

 

For a dT of 5K you need approx 3 l/min per kW so ideally 30 or more. If the flow is 2l (presumably /min) round the circuit but 20 on an isolated HP (how did he bypass it to test that?) then the problem does not lie within the HP so a plate flush will not help. Unless you have an external plate HX as well.

 

DIY with Fernox F8 would be my course of action, supposing I believed the diagnosis.

• What kind of filter have you got and is it in the return line immediately upstream of the HP?
• How often has it been cleaned out and what did you find?
• What does the water look like?
• Did he test it with e.g. Adey diagnostics?
• Does it smell?
• If you leave a few nails in it for three days do they go rusty?

 

If it has anti-freeze valves you do not need to add antifreeze anyway, and you are probably better off without it. Just use an HP inhibitor, and maybe a biocide as well if bio-fouling has been identified as a problem.

 

 

Edited October 31 by sharpener

[JohnMo]

Sounds a rip off.

 

Explain your system, is this the heat exchanger in the outdoor unit or one inside the house?