Grasslin FM1D20A 120 PLEASE....I need a full programming manual on this unit. It was installed in a brand new Engineered Air rooftop air cycling unit last fall and it is a nightmare to program. It doesn't matter how much time I spend looking at it, I can't figure it out, and I'm a maintenance man. So very frustrating. I need to be able to set up multiple on and off times per 24 hour period and can not do that. HELP! Our new technician came in last month and he couldn't figure it out. If you have a program guide for this timer and can share it I'd really appreciate it.

it sounds like no communication from stat to board. cable connections

The rooftop RV Air C0nditioner does not use the battery at all to power anything, there is a transformer in the coach that reduces the 120 volts to 12 volts to the thermostat for safety, but that is never ran by the battery if without high voltage supplying the
12 v control voltage, in fact you can remove the battery and it will have zero effect upon the roof top unit.
The propane furnace with it's 12 volt blower motor will run off the battery alone but not for long, you will need 6 x 6 volt golf cart batteries to use 12 volt power very long, no single 12 volt deep cycle battery has sufficient capacity to single handedly operate much for long.

Have you checked location of probe for return air? Remove filters and find probe to make sure it is about in the middle of flow of return air. Let me know what you find.

Make sure your tstat is programmed for electric, not gas. Or in the settings you want that the TSTAT CONTROLS THE FAN.

If you need further help, reach me via phone at https://www.6ya.com/expert/thomas_092728000e6acb79

Sounds like you have fan in the "on" mode instead of "auto" mode. Here's a link to download an operators manual for that system. Should help.

http://www.dometic.com/FileOrganizer/1-international/Operation%20&%20Installation%20Manuals/Air%20Conditioners%20-%20Vehicles/Comfort-Control-Center_operation_EN.pdf

Digi 20E-120 is 16Amp 120Volt flush mount digital timer with 20 or 140 programs per week.
Grasslin Digi (digi tal/ digital) can be reset using reset button.
Reset might restore functionality, but will delete all programming.

Check that circuit is delivering 120Volt and that circuit is clean without interference.

Also check electrical terminals fit tight on the timer.
Use needle nose pliers and pull terminals off and then push back.
The digi series has 5-day program back-up capacitor so programs should remain, but capacitors go bad.
Power surge can blow out timers. Use surge protection on all circuits.

There are a many Digi timers from years of manufacture by GE and now Intermatic, since Intermatic bought Grasslin from GE.
The digi can be replaced with simple-to--program FM1D digital timer.

Replacement crossover is FM1D20E-120
Open following link for FM1D manual and Digi manual
http://waterheatertimer.org/Woods-timers-and-manuals.html#FM1D

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.

Quite often that indicates no hydro ( 120 VAC ) getting to the unit. Check all breakers are on and 120VAC getting to control box.

Possible overcharge or bad breaker. You need to check the amp draw for the unit. If you draw under full load amps and trips breaker breaker is bad.Rus

Actually, the dealer is somewhat correct. In the hotter months of the summer, the rooftop units have a tendency to freeze up if not run on high cool due to the lack of air movement across the evaporator. If the unit fines on High/Cool, then run it in that mode but adjust the thermostat.

It should not however, cycle on and off that fast unless you have a bad freeze switch or the incoming AC is too low. If during that 8-10 seconds, the air begins to get cold and then it shuts off, then I would say you have a bad freeze switch. If it runs fine on high, but shuts off in low, I would say it is a lack of air movement.

Hope this helps,

Jeff

Rate me please!!

You really need an Ammeter to check this problem. Just because it is a brand new unit does not mean that there isn't a problem with it. Is it run off of a wall thermostat or manual controls? The compressor has a thermal overload switch on the top (under the plastic cover) that will take the compressor out of the circuit if it gets too hot. However, if the entire unit is shutting off, there is another problem. Selector Switch? Thermostat? Let me know what kind of controls you have and we can go from there.