daikin vrv II not heating
hi, i've been working on a daikin reyq16mw1b (R410), no master slave set up just single vrv with 13 fan coils on unit, had problems with no heat.. well very little heat, getting 125 suction and 200 on discharge giving me about 22oC on th3 on indoors, which is definatly far to low... checked eev's which are ok and solenoids are energizing.. want to know if anyone has had this problem before and how they rectified it?? has their been any issues with blockages on strainers before the solenoids because this is the conclusion i'm coming too, i know the right amount of gas is in unit as i reclaimed and weighed back in, carried out the self check and get E3 fault (high pressure actuation) cant think of anything else other than a blockage so have ordered strainers and will change them later this week.. but if this doesnt work what else would you fella's suggest??
am i maybe looking over a simple sollution?!?!
DoD
Re: daikin vrv II not heating
Most R410a systems have heating target of 29 - 30 bar discharge
Why is your system not getting to target pressure ?
Is the compressor ramping up to max speed ?
With the cold ambient temperatures you have at the moment why is the suction pressure so high ?
With sub zero ambient & frost on the outdoor coil the suction is often lower.
1/ Look carefully to see no high to low bypass at outdoor unit like poor operation of 4W reversing valve.
2/ If compressor not ramping up to max investigate correct high pressure sensor data because if the sensor gives incorrect data to the circuit board so that circuit board thinks the pressure is 30 bar when it is actually on 14 bar then the compressor will ramp down.
Both could explain HP fault in the memory.
1 Attachment(s)
Re: daikin vrv II not heating
Hi DoD,
I agree with all of Thermatechs recommendations, they’re all spot on :D
In addition to this I would suggest you also check the following.
Quote:
With the cold ambient temperatures you have at the moment why is the suction pressure so high ?
With sub zero ambient & frost on the outdoor coil the suction is often lower.
The target Te will be set approx 5 C lower than ambiet temp.
Quote:
1/ Look carefully to see no high to low bypass at outdoor unit like poor operation of 4W reversing valve.
Use a temp probe to check reversing valves entering and leaving pipe temps. when doing this, check the temps at least 100mm away from valve. If you have a temp increase of >4 C across suction pipes you have a high to low bypass within the valve.
Notes:
- Valve energised = heat exchanger operates as evap.
- Valve de-energised = heat echanger operates as condenser
- You may find that bottom heat exchanger (smaller reversing valve) is operating as a condenser depending on operating conditions.
Check there is no bypass across Y7S solenoid valve (looking into unit this is the right hand valve of the 2 with large green coils). This valve will be closed when outdoor is operation in heating or heat recovery.
The connected vertical pipe is LP and the horizontal pipe is HP, again this can be checked for a temp increase across the valve.
Also check Y6S liquid line solenoid is energised, this must be open when operating in heating or heat recovery (small valve in left hand bottom of unit with the coil mounted on horizontal valve stem).
Quote:
2/ If compressor not ramping up to max investigate correct high pressure sensor data because if the sensor gives incorrect data to the circuit board so that circuit board thinks the pressure is 30 bar when it is actually on 14 bar then the compressor will ramp down.
Both could explain HP fault in the memory.
To check this you will need to measure the dc voltage across the white and black cable cores at the HP press transducer PCB connection (red 5 pin plug connected to X46A). You can then cross reference the dc voltage with attached table and check with actual press measured on your manifold gauges.
IE. 2vdc = just under 2MPa (20bar)
- Plug red & black wires = Constant 5vdc supply to transducer
- Plug white & black wires = Variable 0~5vdc feed back to PCB
Your problem could also be caused by a faulty outdoor EEV, has the outdoor PCB been changed? If so I would double check all 3 EEV's are connected to the correct PCB connection.
Attachment 3279
Re: daikin vrv II not heating
There was a design fault with some VRVII 3 pipe outdoor units, there are 2 right angle solenoid valves (about 3/4" pipe size). Check the suction pipe temp at the compressor, if it's warm trace it back, I gaurantee it will be coming from one of the above valves (letting by from the discharge).
Some were manafactured with a gauze filter designed for ONE way gas flow, when flow direction changed the gauze gets blasted into the valve and prevents it from fully seating. I have changed several of these. Also woth checking the firmware version of the outdoor, as there were several critical revisions on VRVII.
LAF.
