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Two Holding Plate Configuration

PostPosted: Tue Oct 22, 2013 7:11 am
by JDouglass
I am very interested in the 2M DIY System. Is there a way to modify the configuration to allow me to build both a freezer and frig on the same compressor? I would also like to upgrade the thermostat to digital right from the start. would it be possible for you to post this configuration on this forum?

I understand that I will need to purchase two holding plates sized appropiatly for the boxes. Are there other issues, those of us interested in this type of configuration, should be considering?

thanks very much in advance.

John
S/V Sargo

Re: Two Holding Plate Configuration

PostPosted: Mon Oct 28, 2013 11:43 pm
by RPARTS Tech Support
John,

The two holding plate configuration for the System 2M is possible but could present some challenges. Since you can only satisfy the needs of one holding plate at a time, it is essential that the pull down time of either plate not interfere with the cycle of the other plate. The key question will be how long is the cycle time for each holding plate and can those two cycles be interleaved with satisfactory results.

The concept is to build a daisy chain (or priority chain) using the contacts of digital thermostats along with solenoid valves to connect the plate being cooled to the compressor. The first thermostat in the chain is the highest priority and whenever it requests cooling it's solenoid valve would be open. Anytime the first thermostat in the chain is requesting cooling, the second thermostat is disabled and it's associated solenoid valve would be closed. Once the first thermostat has reached the setpoint the contacts of that thermostat would allow the second thermostat to request cooling and close the second solenoid valve.

This can also be done with mechanical thermostats but in that case additional relays are required to get enough contacts to control the daisy chain and the solenoid valves.

Which are you planning digital thermostats or mechanical thermostats? Please let me know and I will prepare a drawing and post it here.

Regards,
RPARTS Tech Support

Re: Two Holding Plate Configuration

PostPosted: Mon Nov 04, 2013 5:11 pm
by JDouglass
Thanks for your response, sorry for the delay in responding, I'm interested in the digital thermostats.

On my last boat I had an old Glacier Bay system. they had a very interesting feature that ran the compressor at a higher temperature set point when the engine was running (extra power). Is this possible with your digital thermostats?

thanks for your help,
john

Re: Two Holding Plate Configuration

PostPosted: Wed Nov 27, 2013 12:58 am
by RPARTS Tech Support
The ECM digital thermostats listed on the RPARTS website have the feature which enables the alternate setpoint that is activated when the engine is running. You can find them by searching ECM using the quickfind located at the top right of the RPARTS website.

Also, I am working up a parts list as an addition to the System 2M which would allow for two plate operation. I will provide the list to you and also add the list to the System 2M page within the RPARTS website.

Hope this helps,
RPARTS Tech Support

Re: Two Holding Plate Configuration

PostPosted: Wed Dec 18, 2013 12:36 am
by RPARTS Tech Support
Here is a first drawing (see attachment) showing the temperature control for a dual plate addition to the System 2M. Next I will add solenoid valves and an ECM version.

Re: Two Holding Plate Configuration

PostPosted: Mon Dec 30, 2013 3:14 pm
by JDouglass
Thank you very much Tech Support.

I look forward to seeing the next drawings. Is there someone I can speak with to help me with a material's list for these enhancements?

thanks again, I look forward to building this configuration.

John