walk in freezers

[johnnyboy]

What is the position with fitting pressure relief valves or vacuum vents to walk in Freezers. The walk in modular freezer is 2mtrrs by 1.57mtrs internal measurement. Does a unit of this size require a valve or is it sufficient to disconnect the internal fans via a door switch :confused:

[Frikkie]

I had a freezer room where people blocked the vent. It used to blow the door ajar when it started to run again after defrost.

[Shibhrac]

I would suggest that, the ideal location for Pressure relief port for a walk in freezer like yours is in the door side and the reason is to safe space.

[sean1]

i would nt fit one on a room that size unless you have a problem i was led to believe a room that size the evap drain would be suffient

[lowcool]

definitely fit one as they come in different sizes,preferably opposite evaporator discharge and in a corner were air pressure is more likely to be lowest

[johnnyboy]

Thanks for the advice. I had my suspicions that anything less than 3 mtrs square does not need one but could not find out why. The 22mm copper drain should deal with any pressure changes

[johnnyboy]

Thanks for the response. I have used a Carel mastercella controller for the first time on this freezer which is supposedly an all singing and dancing way of controlling freezer temperature. Too many parameters to configure for my liking but seems to be controlling well.

[paul thompson]

the carel mastercella controllers are great . i use them on my coldstore installs

[acnerd]

My understanding with those is to alleviate pressure build up in the room after a defrost causes a positive pressure. I suppose equalising the pressure through the drain is a good way of keeping it clean!! :p

(Of course it's also there to make opening the door easier too!)

[old gas bottle]

should allways fit one realy,near the door if possible,useing the drain can bring its own problems,ie iceing up and draging foul vapours or odours into the box other thing,as allready said is the blowing open of the door,that only has to ruin the stock once with a customer and you might end up with a large bill if the insurance company come after you.also damage to the box structure can take time,;)

[Grizzly]

Guys!
I am confused here!
Surely the defrost drain line has a water trap in it?
Preferable external to the room.
Otherwise are you not freezing the ambient air outside?
A relief valve is important otherwise if you have a good door seal and the room is Low temp.
The pressure differential can make it extremely hard to open the chamber door!
Add a slightly leaking seal that freezes up over time and it can be very difficult to open the door.
Cheers Grizzly
OOP's OGB has beaten me to it! Good sensible comments all the same.

[lowcool]

another thought is implosion,by the way i reckon mastercella are over priced for what they are

[johnnyboy]

Cheers guys. The coldroom was supplied by coldkit and I have now spoken to their technical department (lawrence) He said that their fitter did not fit pressure relief valves on anything less than 3 metres square. One point did cross my mind though. If the door closed behind an operative after a short period of the door being open would the pressure relief valve aid in getting out of the room considering the fact that the pressure drop due to the influx of warm air would make the door difficult to open. :confused:

[old gas bottle]

sounds like penny pinching to me.:(i would get a hard copy of that policy and keep it just in case,;);)