404 condensing unit to 407 Blower

[Rivelino]

Hi All
I've just got back in to the trade after a number of years out and got myself Fgased last year. After leaving the trade in the late nineties (for various reasons) the big learning curve is the replacement gases. From what I've read 404a and 407c aren't poles apart but there is some significant difference in glide. I have an Aspera condensing unit running on 404a and an evaporator running on 407 i.e. what they were both designed to run on.

The blower is a Beermaster single fan with an externally equalised TXV. Although the markings from the pot have disappeared as far as I can make out it's the same relay used with the Embraco 1 and 1/4 HP unit, So the pairing isn't a million miles away. When I used to get a lot of free trade (cellar coolers) previously I nearly always used a 1hp unit and perhaps on the odd ocassion used a 1 and 1/2 HP L'Unite unit. I know it's not an exact science i.e. keeping a room in a pub to 55f/12c as it is a freezer room to -20 but my thoughts are that I could get away with a straightforward TXV change. I would naturally have to make note of the amendments on the evaporator. Any help greatly appreciated

[1mikeefc1]

R404 a for freezer room and r407c for a cellar, tev/ orophis will require replacing but check the oil compatibility if your changing from one to another and a good blast through with nitrogen as well.

[Rivelino]

Thanks for the response Mike, yes with a lateral thinking refrigeration head on the evaporator is no more than a coil with a metering device. I think I confused the post with the mention of freezer room. The condensing unit (with the Aspera pot @ 1hp) is on 404a and was coupled to an old beat up Searle single fan (from a redundant cellar/pub) and I had the opportunity for the single fan Beermaster evaporator, but on 407c. I could grab the TEV from the Searle but it was internally equalized. I remember typically using orifice 1 or 2 previous in the TEV's but will grab the tech data from Wolsey and confirm. Thanks for the head up I'll also blast through with nitrogen. BTW whatever happened to NRS were they bought by Wolsey.

[monkey spanners]

NRS is now Climate center. Think Beermaster is basically just a searle evap with stickers on. Prefer R404A, R407C is sh!t imho.

[1mikeefc1]

Agree with monkey spanners 404a I find better working with 407c can be temperamental.

[Rivelino]

Thanks for response. Also 407 seems a bugger for leak checking on vapour side. internally equalized valve has now become externally equalized after checking as external access/port has a 1/4 blank on it. Will hopefully be able to contribute and help with other posts.
Cheers

[Rivelino]

Agree with monkey spanners 404a I find better working with 407c can be temperamental.
Mike, just to come back to this what typical pressure would you put through for flushing i.e. 5 bar, 10 bar. Also if I wanted to put something in temporary (cheap and cheerful) to separate any residual oil (to be safe) could I put in something like a U trap in the return with a bleed (schrader) then remove after 1 month. Cheers