Reversing valve problem?

[coffeebreak]

Being new to heat pumps reversing valves are also new. An air con unit works fine on "forced" cooling but when I try on heat mode the compressor starts for a while and then cuts out. The solenoid is o.k.This fault happened after topping up the unit. Is the valve at fault?Has it stuck in cooling mode?Has it frozen in position? Any ideas

[nike123]

Being new to heat pumps reversing valves are also new. An air con unit works fine on "forced" cooling but when I try on heat mode the compressor starts for a while and then cuts out. The solenoid is o.k.This fault happened after topping up the unit. Is the valve at fault?Has it stuck in cooling mode?Has it frozen in position? Any ideas

Did you recover refrigerant and then charged by weight?
It looks like overcharging.

[coffeebreak]

the unit was operating poorly in heat mode so after checking pressures i topped up refrigerant. the problem occured after this. Is it just a case of removing some refrigerant or is there another option?

[nike123]

the unit was operating poorly in heat mode so after checking pressures i topped up refrigerant. the problem occured after this. Is it just a case of removing some refrigerant or is there another option?

When you checking pressures you also need to check temperatures, air quantities and humidity in order to know what is happening in air conditioner. Simply checking discharge pressure cannot tell you that system is undercharged or overcharged.
In order to simply, surely and quickly establish what is going with split-type air conditioner, easiest thing to do is (by my experience) to recover and weigh refrigerant and then act accordingly.
It takes about half hour to find about lot of things.
In the meantime you could chit-chat with customer and even drink 1 beer.

[thermo prince]

Nice one, Nike123,
You sound like my good Czech colleagues in Prague & Kolin - they invariably take me for " good Czech food " whenever I visit - dumplings & beer, more dumplings and beer !

regards
T-P

[nike123]

Nice one, Nike123,
You sound like my good Czech colleagues in Prague & Kolin - they invariably take me for " good Czech food " whenever I visit - dumplings & beer, more dumplings and beer !

regards
T-P

I understand them, this is my favorite supplier of parts :

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http://www.mediafire.com/imageview.p...2gnyj0&thumb=4

Guess, what is my favorite part!

[Brian_UK]

Coffebreak, do not 'top-up' when in heating mode. Your superheat readings will go haywire.

Do not 'top-up' at all. If it was short then find the leak and recharge by weight.

Reversing valves need a pressure differential across them to operate, if the system has pressure problems then the valve may not work correctly.

[ChillTechnican]

Coffee , is the unit going out on high or low pressure??
What sort of expansion valves does the unit have?
There could be a problem with one of the Txv if these are in the unit, I had a similar problem lately , thought it was reversing valve not fully moving, but turns out it was the power head on the indoor unit. The unit would work on heating but on cooling low pressure would drop into vacumm.
hope that is some help

[paul_h]

Are all the fans working? What is it cutting out on? overload, HP cut out, thermistor protection (eg compressor discharge over heat)

[Springbok]

Hey there..yep,best to recover and recharge by weight...does the compressor automatically restart or is it manually done?Best to check the wiring to the comp to see where it stops...hope it helps...

[norfolkboy]

hi, just a thought is the air handler too small for the condensing unit, i had a similar problem with the air handler too big and if charged for heating it flooded the condenser in cooling and tripped on hp.

[davej]

one of our young engineers is having a problem with sinilar fault at the moment, i have been trying to find some idagnostic info on these valves ( had some somewhere but cant find it now!!! )
anybody got any links to info ?

[nike123]

http://tinyurl.com/2qppyc

[davej]

thanks Nike 123 i have printed that for him,

why do the posts come up a different way round when i log in to the way they are when i am just browsing???

[jason09]

how can you say to recharge the system! unless im missing something he did nt even tell us what the pressures where!
there could be problem with the defrost control, it could be anything!

[nike123]

thanks Nike 123 i have printed that for him,

why do the posts come up a different way round when i log in to the way they are when i am just browsing???

I really don't know.

[nike123]

how can you say to recharge the system! unless im missing something he did nt even tell us what the pressures where!
there could be problem with the defrost control, it could be anything!

Yes, you are missing!

This fault happened after topping up the unit.

[Gary]

Unfortunately, a great many service techs believe that pressures are a direct indicator of refrigerant charge. Sorry, it doesn't work that way.

At the extremes (grossly undercharged or grossly overcharged), yes the pressures are about the charge.

In between those extremes, the pressures are almost entirely about the temperature and volume of the air flowing through the coils.

[Brian_UK]

why do the posts come up a different way round when i log in to the way they are when i am just browsing???

It depends on how you have set up your account to view the forum.

When 'just browsing' you are at the forum defaults.

When you log in then you are at 'your' defaults.