faulty EPR on coldroom

[fazzamouse]

got a coldroom running off a pack,temp not dropping below 7 degrees,coldroom has 2 searle evaps and they are just sweating at the exp valves,EPR on top of coldroom a block of ice,adjusted it the other day and coldroom ran fine for 2 days,pressure at EPR 75p.s.i,EPR will not adjust and in my mind is goosed,would it matter if i linked it out or would it be best to replace with new,advise please.........

[nike123]

Ignore!.....

[fazzamouse]

not that simply when it keeps triggering a rdm alarm........

[nike123]

not that simply when it keeps triggering a rdm alarm........

I mean ignore my post because there is no possibility for me to erase it!

[coolhibby1875]

is this a m@s site?

[Gary]

... pressure at EPR 75p.s.i,...

Telling us the pressure is meaningless if we don't know what refrigerant is in the system... and we would need to know the pressure both upstream and downstream from the EPR.

[Porkington]

I'm sure Fazza is the person who got a job with City recently. Without checking the old thread im not certain.

Anyway as Gary says, we need more info.

[fazzamouse]

pack is on 404a,pressure at condensing unit is 50p.s.1,pressure at EPR 75p.s.1,sorry not got reading at evaporator will check that on monday when i return.

[Gary]

pack is on 404a,pressure at condensing unit is 50p.s.1,pressure at EPR 75p.s.1,sorry not got reading at evaporator will check that on monday when i return.

Are there any devices between the EPR and the condensing unit that might be restricting? It's possible that there might be a SORIT valve or similar device at the suction manifold.

Will the EPR adjust to a higher pressure?

[fazzamouse]

the epr is open fully no adjustment left,no other devices between epr and unit,pack runs about 20 metres of multidecks and 2x coldrooms,just getting high temp on this coldroom

[Gary]

the epr is open fully no adjustment left

Does adjusting it in the other direction change the pressure? If it will adjust above 75psi but not below, then the inlet is restricted.

[Chunk]

Are we talking about an electronic EPR? And is the frost just on the pack side of the valve?

[fazzamouse]

just your standard alan key adjusting value,the best i could get it to adjust to at epr on friday was 58p.s.i,just dialled into store and coldroom back at temp,****y e.pr?

[Porkington]

If its your standard Danfoss EPR that they tend to install in this country then it sounds like its fubar. You should be able to wind that sucker right down.

[Grizzly]

If its just a case of poor suction pressure control.
Change the epr as it sounds as if it's passing.
Do not bypass it!
Grizzly

[Billy Ray]

pack is on 404a,pressure at condensing unit is 50p.s.1,pressure at EPR 75p.s.1,sorry not got reading at evaporator will check that on monday when i return.

Sounds like the suction pipe between cold room & pack is too small or overloaded! 25psi pressure drop is excessive..

possibly it may be the scenario that when other decks go offline the suction pipecopes with the load.

Billy Ray

[coolhibby1875]

do not bypass this epr you really must change this for new as your room will be operating at diff temp from the multi decks so instead of fitting a satilite system to the pack you install epr valves to achive the presure change you will also find this a lot on fresh meat cases on packs

[tony--1]

wat is the pressure range on the epr ? it will say on the body .ie 0-60 psi ?
it could be the inserts in the tevs .are to big ?

[tony--1]

tevs may have been adjusted to much

[tony--1]

75 psi would giv you a evaporating temp of about +1.no way will the room come down to temp.50 psi about -8,it looks like its u/s to me . fit a new valve

[andyrobbo]

Sounds like the suction pipe between cold room & pack is too small or overloaded! 25psi pressure drop is excessive..

possibly it may be the scenario that when other decks go offline the suction pipecopes with the load.

Billy Ray

The EPR is the restriction. There is obviously a problem with the valve. The EPR's job is to restrict flow to raise the backpressure to the required SET of the Room.

[Gary]

just your standard alan key adjusting value,the best i could get it to adjust to at epr on friday was 58p.s.i,just dialled into store and coldroom back at temp,****y e.pr?

We need the pressures both before and after the valve, because the upstream pressure can't get any lower than the downstream pressure no matter how much you adjust it.

For example, if for some reason the suction pressure at the condensing unit goes up to 100psi, then the EPR pressure will go up to 100psi, regardless of the setting.

[750 Valve]

The EPR is the restriction. There is obviously a problem with the valve. The EPR's job is to restrict flow to raise the backpressure to the required SET of the Room.

andyrobbo is in da house!!! when do you lob in sydney again pugz?

[tony--1]

We need the pressures both before and after the valve, because the upstream pressure can't get any lower than the downstream pressure no matter how much you adjust it.

For example, if for some reason the suction pressure at the condensing unit goes up to 100psi, then the EPR pressure will go up to 100psi, regardless of the setting.

Gary it does say in 1 of his posts

[Gary]

Each time he tells us the upstream pressure, we also need to know the downstream pressure.