Mitsubishi 1301 low pressure fault.

[...CooLMan...]

hi,

I've got a mitsubishi PUHY-EP200YHM-A out on a 1301 low pressure fault. I've checked gauge pressure against 63LS LED reading and it looks like the sensor is dead. gauge 8.5 bar sensor 0.3. Put the the HP sensor into plug for the LP and the reading is good.
It looks like I've got my first LP sensor to replace and I really could do with some tips.
Thanks in advance..

[marc5180]

What would you like to know?

[still learning]

its a recliam of the gas then .
and you can check the charge .
i would get on all four ports ( both the outdoor ports and the pipe work going to the rest of the system) .
un braze the old switch , and the braze in the new one whilst purging with ofn .
and wet rag wrap the new switch .
if the charge is good , replace it after pressure testing ( check the pressure rating of the switch ) and vaccing .

[...CooLMan...]

Thanks, that sounds like a plan.
I wasn't sure on the fitting of new sensor. Also if old charge is good Can just close liquid and gas valves to pipework and pressure test the outdoor unit?
I've got about 65kg to reclaim. The unit is twinned to an EP300. If I can get the system to run for a bit can I speed things up by pumping direct from hp pipe port. ??.
Cheers

[marc5180]

Thanks, that sounds like a plan.
I wasn't sure on the fitting of new sensor. Also if old charge is good Can just close liquid and gas valves to pipework and pressure test the outdoor unit?
I've got about 65kg to reclaim. The unit is twinned to an EP300. If I can get the system to run for a bit can I speed things up by pumping direct from hp pipe port. ??.
Cheers

Have you checked with Mitsubishi to see if they do a low pressure kit? I know for the high pressure sensor they make a kit that you can connect to another part of the system (high side) and so can change the hp sensor without having to reclaim any of the refrigerant.
That would make it much easier.

If you do decide to recover all the refrigerant in order to change the sensor then I wouldn't try and close the service valves at the outdoor because you won't know if they are slightly passing and if you pressure test the outdoor after changing the LP sensor and find that they are passing then you will have nitrogen mixed with R410a and it will be a nightmare to get it out of the system.
Definatly not worth the risk.
Is just recover the whole charger, that way you know there won't be any issues.

[...CooLMan...]

Thanks Marc,

I was planning on reclaiming all the refrigerant removing faulty sensor purge whilst brazing in new part and then closing the service valve and pressure testing ODU. If they are letting by I could lose a bit of time on the job so might aswell pressure test the whole system. Need to check the charge fist anyway.
I look into the the low pressure kit. I spoke it Mitsubishi on Friday and they didn't mention it.
Cheers

[...CooLMan...]

Hi,

I still haven't been back to site. The low pressure kit has been quoted for but we have yet to start the work.

I'll post my results if I'm the one sent back to do the job..

Thanks again for the advice..