Mitsubishi VRF DFC leaking condensate

[moondawn]

Hi all, on a site we have a DFC which has a gravity drain the gravity drain is 21.5mm and is joined to another dfc. problem with the drain is that it is not gravity and not moving the condensate away. previous engineer has been to site and fitted 1 x aspen universal pump and has capped of the non gravity drain, basically 1 pump doing two ducted fan coils condensate these are big dfc prob size 80s

the complaint is water coming through the ceiling, i have looked at the work briefly and could see that water was collecting in the tray and air movement from the fan was making the condensate act like a wave which i imagine is slaphing over the top and out the tray onto the ceiling.

why would the condensate in the tray act like this could it be that the unit is not sealed properly with air escaping causing this problem
Also do you think 2 pumps would be required. one for each unit as thats what i would of done if i had gone to re do the drains?

advice welcome really guys

cheers moondawn

[install monkey]

can u raise the ducted unit on its rods?
mitsi ducted driptrays are on the positive side of the fan so no issues with holdin back water,any lift pump on the ducted but they used to gravity drain stubb

[moondawn]

Hi install i will look at the rods however think the fan coil is pretty much touching the ceiling.
Bit unsure what you mean by they used to gravity drain stubb? could you clarify?

[install monkey]

some ducted units have a gravity drain stub and also a drain stubb higher up to allow u to connect to the internal lift pump therefore u get upto 550mm head off the unit, the water in the drip tray will be ccausing waves from the air velocity over it as the condensate cannot run away,
fit a 2 ltr tank pump to it and run the 3/8 braided hose to a toilet stack- use them drain connectors that pumphouse do- drill an 8mm hole stick in the connector and screw it up till the rubber bung expands

[moondawn]

hi install,
The dfc does not have an internal pump only has a gravity drain pan.
the pan is basically sat on the plasterboard ceiling so a tank pump is a no go unfortuanlty. not sure if any other pumps on the market are gonna be better than the aspen peresltic pump currently installed.
with the condensate not running away i reckon 1 pump for two large sized dfc units is not enough. what do you think should it be 1 pump per unit.?

[install monkey]

if u cant get a tank pump in then a mini aqua or mini orange- glue the float enclosure inside the drip tray- tray will be approx 8mm deep in water and the pump will kick in,pump is good for about 30ltr an hour- bit of a bugger to clean the gauze but if u can remove the plate near the pipework stubbs then it might be a go er!!
gotta be 1 pump per unit

[moondawn]

hi thanks for your advice might go with aspen mini orange pump, was pretty sure 1 pump doing two trays would be insufficeient but good to get another engineers take on it. so thank you.
not used mini aqua so will check that out.
have you had any experience of fitting a aspen standard pump? never fitted one before how would that be wired in to a mitsi dfc?

cheers

[install monkey]

oh even better get a mini lime or sauerman delta- 2yr gaurentee on sauermans- get a drain stbb adaptor- peice of rubber than goes from 1 1/4 to 1/2 - do different sizes- white,black,green- then make sure the pump is supported- universal pumps just connect to the live,neutral and have 2 sensors meant to be on return air,supply air and when it detects a difference of a few degrees kick the pump in- then when unit stops cooling it runs for a further 3 mins- not good on an inverter as with low output the pump wouldnt kick in- causin the drip tray to back up-perisaltic rubber is meant to be replaced every 12mths but no one bothers- also can be noisy whirring away.
so the pump is mounted externally from the unit to make servicing easier

[moondawn]

hi yeah fitted lots of universal pumps but was interested in the standard pump you require wiring in for a cooling signal instead of sensors have you fitted these. if so where do these wire in on a vrf dfc?
yeah thats a good idea so could mount a aspen mini lime on the end of the drain stubb via a rubber connector. might be best option that mate

[install monkey]

standard aspens with the cooling signal req 150-240v ac - u cant fit em to a vrf as u only have 240v supply and the 30vdc m net
aspen do options of a float contact, just read they have a compressor sensor option too
http://www.aspenpumps.com/en/peristaltic-pumps.html

[moondawn]

cheers mate thats what i was thinking how would they be able to be wired in as cooling signal is done via the mnet. i have fitted tons of universal pumps but not 1 aspen standard.
cheers

[install monkey]

only way of fitting a standard to a vrf would be to fit a room stat/duct stat to maake if supply temp under say 18deg or a pipe stat on the suction line to start up if pipe under say 15deg
to switch a permanant live to supply your signal wire- would love to see piccys of the previous handy work

[install monkey]

http://www.pumphousepumps.com/GroupInfo.aspx?Id=206
details on the reducers and the soil stack connectors

ps clean ur old messages- u can only have 50

[moondawn]

cheers mate think with the above advice i have a very good idea what needs to be done. one more thing the aspen maxi lime says 32 ltrs an hour and the aspen min lime says 12 ltrs an hour. how much condensate do these dfc produce an hour very roughly as i know there will be many factors.

[install monkey]

rule of thumb is 1ltr per kw-
http://www.sauermannpumps.us/uploads...0SIUS23_02.pdf
bear in mind flow rate is dependant on head and length of run.
says sauerman is 10ltr per hr and good for upto 20 kw
bear in mind also ur drip tray will hold back a lot of water so ur ok, if it was a wall mt then ur tray would only hold about 1/2 ltr of water

[moondawn]

thats great i will apply that rule of thumb from now on.

cheers for all your advice.