REST/Booster Engine Pre-heat with DPDT Switch Modification

ok... all that outa the way, back to bizness:

replaced the coolant pump...

finished running the 16/4 cable up to the console and got its panel off
cut-in+mounted the rockerswitch
used a DPDT center off, with indicator lights (12v rated/20a carlingswitch, from grainger)
got the REST/bypass ckts all hooked up at the helm....
pressed the rocker switch fwd...
and waited...
the blower spun, i could hear the pump and coolant flowing in the dash area...
about a minute later and VOILA! that now familiar and comforting ROAR as she lit up! (the D5)
let it run til the REST timer shut it down (guess it was 1/2nhour) and then cranked up the main.
temp gauge at that moment was at the 135 mark, with nice warm air coming out the vents (in sunny low 40s wx)

the cabin was warm prior, as had just shutdown the D2 before firing up the 5 (since i have the 2 tapped into the 5's OEM fuel line)
so... so far so good... just not yet sure what'll happen on sw pos#2 ?

but hey!
it all seems to be working as described/expected.


to the vic meister!

ok here's some operational benchmarks (seeing as both the D5 and the coolant circ pump are new)

data collected with 2 fluke DVMs, 1 with a fluke DC ampclamp plugged into it
(on a 4ft cord so can view inside, at the helm), clamped on batt NEG to the firewall main GND
in mostly cloudy 44degF wx, starting with a cabin temp of 49deg at about 1430MST, after a low of mid30's overnight
2day rested crank batt volts: 12.52 (4 yo, mfd oct2014, still glows+cranks strong)
max amps during glow phase: 15-16a (IIRC as i fergot to write that down when it was happnin..)
after ign phase: 8a with REST blower set on min/0 (but blowing)
batt volts climbing back up to 11.95 (think it pulled down to 11.8 during ign)
after appx 20mins runtime, cranked up fanspeed to max (on REST ops = 1 notch below HI)
amps then at 9-10, with 130degF air coming out of HVAC vents (1 dash + defrost, other 3 closed to force more aft), cabin temp upto 52deg

after appx 28mins runtime: 142deg air from vents, cabin temp at 55
batt volts 11.93, with 9a draw; tl appx drawdown of 5-6ah (?guess)

REST shutdown at 30mins, cranked engine with no glow and she fired right up, with nice toasty warm air out of vents.
my guess would be that in another 1/2 hour cabin temp wouldve been up into the 60s (in 44 wx, no wind)
and would/should still have enough batt to crank'r up...

next test will be to try this at temps down into the 10-15deg range (zeerow if can get it)

Nice stats! Seems to align with my numbers. I guess the only difference is that for the mods I do (understood this is a specific mod thread) there is 0 amp draw at level 0 from the ATC fan motor as I bypass the REST circuit and go straight to the ATC dial relay. The average amp draw from the heater alone after the initial glow pin ignition and while still below ~ 175F coolant temps (still running the furnace blower motor on high and the fuel pump and I'd assume the glow pin is hotter) seems is around 4amps (once again, without the AC motor running), once the coolant temps are > 175 it runs around 3amps/hr on average. This is helpful if your intent is to simply heat up the coolant and not the interior of the rig or if the interior is plenty warm and you want to conserve SOC.. Might be worth looking into if concerned about running the battery down.

Congrats on finally getting the system dialed!

yeah vanski, having this setup run on the housebank is my ultimate plan, would appreciate seeing your setup (pix, diagrams etc)
but wont be going any further til wx warms up (have other priorities these daze
along with a roadtrip down to los wages on the weekend (to meetup with the other1/2's bro+fam for xmas)
where its looking like it'll be almost tropical... (hoteling it on this one tho)


adding: the other thing i want to address, is disabling the HVAC air intake-damper (re-circ button only closes it for 15mins)
so that it stays CLOSED when parked and heating with the espars (vs sucking in cold air)

Due to the recirculated damper being operated by vacuum there is no simple way to operate it with the engine off. Even if you manually trigger the damper solenoid you need to have a fair sized vacuum reservoir in the system. Not terribly difficult to install but does require some extra work. the control solenoid itself is a simple 12v supply. Long ago I installed a manual switch to control the recirculate solenoid, I would never go back to the timer system.

Note that your vacuum system must be free of even the smallest leak otherwise you would bleed out the vacuum and you need to operate the solenoid once the engine shuts down.

the only other option is to create a hook or cable to hold the damper closed, this would be a problem in the winter though as you need fresh air to defog the windshield.

Midwestdrifter said:

..
the only other option is to create a hook or cable to hold the damper closed, this would be a problem in the winter though as you need fresh air to defog the windshield.

Click to expand...

Hmm.. not a bad idea and then you could unhook in the morning to get fresh air to defrost the windows. I would imagine in real cold temps this could make a substantial difference in energy consumed not to mention the heater stands a chance to run on 'low mode'; lower energy consumption and much more quiet.

vanski said:

Hmm.. not a bad idea and then you could unhook in the morning to get fresh air to defrost the windows. I would imagine in real cold temps this could make a substantial difference in energy consumed not to mention the heater stands a chance to run on 'low mode'; lower energy consumption and much more quiet.

Click to expand...

Since the DPDT switch questions have been pretty much answered... continued meander.

What about an old school manual choke cable to position the fresh air damper. It would give positive control (even mid position capability) and not use any energy.

Some of the included parts in this kit may help the install.

Dorman HELP! 55101 Choke Conversion Kit
https://www.amazon.com/Dorman-HELP-55101-Choke-Conversion/dp/B000CO7CK0

vic

Meandering...

I haven’t messed around with the recirculating solenoid and won’t pretend to know a cable type cable choke will work. Anyone? The idea is solid and might make the system a bit more efficient (mostly for the folks running it all night as a stand-alone heater compared to the dpdt switch regulated by the 30min rest circuit).

A linear pull type cable could work, but the pull force is around 10lbs? The actuator has a spring. A electric rotary actuator with linkage would work. That could even replace the vacuum unit, and use the same 12V closed signal? My jetta uses something like that. Only uses power when changing positions.

An electric step type actuator would work too. I doubt it would be near the 12 buck choke unit price point.

Midwestdrifter said:

A linear pull type cable could work, but the pull force is around 10lbs? The actuator has a spring. ...

Click to expand...

The friction type pull knob doesn't need that spring. The cable/knob will hold the set position.

The issues that I see.

Remove the return spring.

Approximately match the bell crank length/movement to the pull knob throw. (The Dorman kit parts may help to do that.)

Route the cable through the firewall to the dash.

Mount the pull knob somewhere in/under the dash.

For my thinking, to accommodate the provided cable length, the knob could even favor the passenger side. It isn't like it needs to be accessed that often. I recall there being some open dash face space and open area near the glove box.

I know that I am simplifying things a bit. I don't recall how much working room there actually is around the OEM damper bell crank.

vic

one way.. or another...
we will make it happen.

Sorry for my limited knowledge but in order for a 7 pin DPDT rocker switch with indicator lights to work, do I just connect the 7th pin to a ground for the ON lights to illuminate? It's a ON OFF ON rocker switch with two indicator lights for each ON. Thanks!

socalmbcruiser said:

Sorry for my limited knowledge but in order for a 7 pin DPDT rocker switch with indicator lights to work, do I just connect the 7th pin to a ground for the ON lights to illuminate? It's a ON OFF ON rocker switch with two indicator lights for each ON. Thanks!

Click to expand...

Ummm... probably.

If they don't specify which set of pins (i.e. which pole) are actually powering the lights, that would seriously hamper using the switch for purposes other than power on both poles.

For that matter, if they're not LEDs and you didn't provide a ground, then you're inviting current leakage between the two ON sides. If they are LEDs, that means the switch must be used to switch the positive side of the circuits, not the negative (since LEDs care about polarity)

--dick

Here is the diagram. Pin 7 supplies negative and 1 & 3 positive for the lights. These are LED lights. Can I use this switch for the modification with indicator lights?

https://www.amazon.com/gp/product/B00P7ZS5GE/ref=ox_sc_act_title_2?smid=A2JE1V94UJXPY3&psc=1

socalmbcruiser said:

Here is the diagram. Pin 7 supplies negative and 1 & 3 positive for the lights. These are LED lights. Can I use this switch for the modification with indicator lights?

https://www.amazon.com/gp/product/B00P7ZS5GE/ref=ox_sc_act_title_2?smid=A2JE1V94UJXPY3&psc=1

Click to expand...

Uhhh.... No.

If you look at the diagram:



The positive power is not being fed to the center post (moving conact) of the switch.
The upper pole (in the diagram) has the fused power arriving on the two static pins, and the moving contact is therefore *negative* relative to those.
The same logic holds for the lower pole.

--dick

I completed the modication a few days ago with a 6 pin DPDT and is working as intended Preheat with REST. However Espar stops after achieving about 134F in 10 minutes. I try to re-engage at 90F and still does not start. Is this normal? I thought it would run up to about 180F and stop. I am in CA and weather here is about 55F to 85F these days. I tried boost heat mode with engine running and Espar stops at 134F again.

socalmbcruiser said:

I completed the modication a few days ago with a 6 pin DPDT and is working as intended Preheat with REST. However Espar stops after achieving about 134F in 10 minutes. I try to re-engage at 90F and still does not start. Is this normal? I thought it would run up to about 180F and stop. I am in CA and weather here is about 55F to 85F these days. I tried boost heat mode with engine running and Espar stops at 134F again.

Click to expand...

The control temperature is less than 180. 167F comes to mind? The temperature control sensor is in the Eberspacher heater. The engine temperature sensor is on the top of the engine. The heater temperature control can hit set temperature before the entire engine warms to that temperature.

vic

This morning Espar ran about 10 minutes and stopped at radiator fluid temp of 115F in ambient temp of 56F. I am mainly going to use it in freezing temp as preheat to overcome 3 non-working glow plugs. Yesterday it achieved 134F in ambient temp of 75F. Looks like Espar stops when it heats up the radiator fluid 60F above the ambient temp in both cases. Not sure if Espar is designed to do this. I am worried if I am at 20F and Espar only heats up to 80F and if that is enough heat to start the engine.

socalmbcruiser said:

... I am worried if I am at 20F and Espar only heats up to 80F and if that is enough heat to start the engine.

Click to expand...

10 minutes of heater operation has been enough for my 2004 when ambient is 0F and lower. You will be fine at 20F. Glow plugs aren't needed above 32F or so. It doesn't take much heat to make a difference.

Added:
Is the heater responding to temperature or is the REST timing early?

vic

That is great to hear! REST continues to run for about 30 min.