mercury climatic

[install monkey]

anyone got a service manual for a mc120a??? its got a trend front end- no option for adding password- thats me next question
also the bugger wont run, flow switch,water and fridge side all ok, water dp sensors ok, return water 29deg, just sat there-not even trying- remote external contacts ok (continuity)

the 2rms relay pcbs- when u link the jumper pins to hand each cop starts ok,4 compressors on 2 circuits- the relay cards have a 24v dc supply and a 0-10v proportionate output- ive e mailed mercury but no doubt theyll offer to send out a chimp for 700 quid a day- goin back to site on wednesday with a bms chimp

[marc5180]

anyone got a service manual for a mc120a??? its got a trend front end- no option for adding password- thats me next question
also the bugger wont run, flow switch,water and fridge side all ok, water dp sensors ok, return water 29deg, just sat there-not even trying- remote external contacts ok (continuity)

the 2rms relay pcbs- when u link the jumper pins to hand each cop starts ok,4 compressors on 2 circuits- the relay cards have a 24v dc supply and a 0-10v proportionate output- ive e mailed mercury but no doubt theyll offer to send out a chimp for 700 quid a day- goin back to site on wednesday with a bms chimp

Service manual, you'd be lucky!!
I don't think they even make them.
Do you have the wiring diagrams?

Is it a packaged mercury unit with boilers and a chiller or just a chiller?
If it is how have you got them switched on at the front of the panel, both to auto or both to hand? I've had issues with this before as well.

Is R2 relay made, if it is then the pumps are running, flow switch is made and most of the safety's on the waterside are made.

What normally holds these things off from running is the trend DP transducer.
It has to be between 15kpa and 50kpa anything less and it won't run. You can fit a potentiometer into AI8 contacts IIRC but only as a temporary measure because after a while it starts messing up the trend for some reason.
If you go into sensors in the trend, it's normally the bottom one that says 'water DP sensor'

Lastly if you go into digital inputs, is there any type of fault showing up?

[install monkey]

this is just a chiller- only got basic access via the front end- general status ok, initially both relay cards were set to off- set in auto- no run set to hand- basically giving 100% demand and all runs ok, but as the trend has to give a variable 0-10v signal to the cards obviously it would freeze- so i put it back to auto - ive sent an email to mercury requesting a manual! haha- all kit is bespoke to order!- optional extras on them machines is sticking 4 compressors in an acoustic box on springs so pipework fractures as the springs have more travel than the flexi's! haha
there is a wiring diagram on site

[marc5180]

If you put the jumpers to hand this will disregard the Water DP sensor, this is located just above the evap PHE to the right of the compressors. It's the thinner one of the two and both of them are red.
Pound to a penny it's this.
IIRC the chiller module gives the output on terminals 400 and 401 for circuit 1 and 402/403 for circuit 2.
If your BMS guy finds that is this the cause then I'd advise to get him to take this out of the controls and use the 2 sensors located on the flow and return as the safety and if this drops below say 3degrees then it knocks off on frost ( he might have to rewrite this into the software but it shouldn't be difficult)
If your still stuck give me a call because I know these quite well.

[install monkey]

ive got 24v ac on 400,401 and 402,403 onto the lil relay card at the bottom
https://www.trendcontrols.com/en-GB/...s/default.aspx
but chiller display is limited- will only let you read the flow,ret sensors and adjust setpoint only, clock is set right- both dp sensors were replaced by others, tested the terminal block at the bottom left- all safetys made- both dp's external switched contact,

[install monkey]

all 4 relays at top right energised

[marc5180]

That link doesn't work, it takes me to the trend page but the page is blank. What is it?
There are 4 DP switches
One for the Evap, one for the pump a flow switch and something else
But the only way that you can tell if the DP sensor is holding it off is through the sensors section normally on the trend but since yours is giving you limited information you won't be able to read it and I don't know what the resistance characteristics are.

Btw I did accept that the other day or I thought I did, I'll log in again now and do it sorry

[install monkey]

http://www.mediafire.com/view/zrr5tu...-uk0yr0212.pdf
2 dp switches i found on the water circuit and just loop through the bottom terminal bed

[marc5180]

Sorry my bad....there's not 4 DP switches there are 2, one for the Evap and one for the pump but there are 4 safeties....
Yours may be slightly different but if you have 240v power on terminals 7-10 in the panel then the CW pump DP switch is made, the CW flow switch is made and the CW LP switch is made. I think the Evap DP switch is terminals 21-22 but I can't remember that one off the top of my head but I'll know on Monday.
If these are made then R2 relay will energise, the trend should give an output for the Cw pumps to start.
If the pumps are running??? Are they? Then the module should give a command for the pumps to run (don't forget to check if T3 & T4 timers are energised, which supply power to the common terminal onto the 2RM boards)


You should have 24v on terminals 416 and 0v on 400 and 402, 401. You say the red lights are on on the 2RM card just above the relays? Is this correct

[install monkey]

green lights on the 2ms cards for power, when put in manual u get red leds to show hand mode- send us ur moby number on linkedin so i can bell ya on wednesday when im pullin me hair out

[marc5180]

green lights on the 2ms cards for power, when put in manual u get red leds to show hand mode- send us ur moby number on linkedin so i can bell ya on wednesday when im pullin me hair out

I'll send it over now. Let me know how you get on either way.