Thermo Valve Conversion Kit

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Thermo Valve Conversion Kit

July 10, 2018, 09:34:15 pm

Some time back I wrote about a common issue of over heating on mountain grades. Despite installing a new radiator, CAC and transmission cooler, I continued to have problems with my coolant temps going well beyond 220 degrees. A number of people pointed to the electronic thermostatic switch which controlled the hydraulic fan speeds. After shopping on line, I found that the replacement was only available from Danfoss for around $900 and that it could also malfunction down the road.
Yesterday I had a pilot (wax) valve installed on the out flow pipe and removed the old switch. This morning we went up a number of steep grades from Eugene Oregon to Redding, CA on Hwy 5 and the temps stayed between 190 and 209 on the various climbs! This was a huge improvement. Also, my fan does not move when the engine is cold, giving me some noticeable boost in acceleration. If anyone has any interest, I'll send out more info.

Re: Thermo Valve Conversion Kit

Reply #1 – July 10, 2018, 09:40:09 pm

I'm curious what a pilot valve is where it was installed at and did you install it

Re: Thermo Valve Conversion Kit

Reply #2 – July 10, 2018, 09:41:47 pm

All ears as my 89 is miswired and have yet to find a wiring diagram.

Re: Thermo Valve Conversion Kit

Reply #3 – July 10, 2018, 09:59:43 pm

Interested.

Re: Thermo Valve Conversion Kit

Reply #4 – July 10, 2018, 10:02:14 pm

Quote from: hdff – July 10, 2018, 09:40:09 pm

I'm curious what a pilot valve is where it was installed at and did you install it

This is what I understand: The valve takes the place of the 2 speed electronic switch which receives input from the CPU through wiring. The pilot valve (to keep things short) is screwed into the downflow pipe from the thermostat via a "weld flange" that was welded over a hole that is drilled into the pipe. The hoses that were attached to the old valve (behind the old switch) are attached to the provided flanges. How it functions: The copper colored probe (see photo) picks up the heat from the coolant flow and causes the wax to expand, opening the lines to the hydraulic fans, allowing coolant to flow, causing fans to turn. When the engine coolant is cold that "bypass" is closed and the fans don't turn until "needed". The speed of the fans are proportional to the temp of the coolant. If someone has a more accurate explanation, I appreciate better info. What I have was explained to me by the mechanic who installed it.

The manufacturer is Dynamic Limited UK and the part is made in Swindon, England. TVCK-101 "Thermo Valve Conversion Kit". In the photo, the valve is on my hitch receiver. I had it mounted inconspicuously near the radiator where the original hoses could be attached.
I bought the kit from Source Engineering in Eugene, OR and K&M Mobile RV Repair up the road in Junction City installed it. Despite the name, the installer has a large professional looking shop. Most of their experience has been with Country Coach. The guys liked my Foretravel.

Re: Thermo Valve Conversion Kit

Reply #5 – July 10, 2018, 10:10:13 pm

Since welding is involved, do both house and chassis batteries have to be disconnected?

Our house batteries are buried and not easy to get to. As full-timers we have to empty a half bay and remove a panel to get to the house batteries.

I have considered doing this conversion. How do costs compare to replacing the existing system of the 2 speed electronic switch?

Re: Thermo Valve Conversion Kit

Reply #6 – July 10, 2018, 10:25:18 pm

Our 97's dynamatic piloted wax capsule fan temp system goes from a "idle" fan speed not off. My understanding is that is because of the intercooler/radiator/trans cooler needing some airflow across it to cool it?

Was not aware of a off on cold startup fan controller. Electric fan was low/high. Not off to the best of my info?

Bet it does spin cold?

Re: Thermo Valve Conversion Kit

Reply #7 – July 11, 2018, 12:18:33 am

Website didnt have a price.. what are we ballparking here and how long did it take

Re: Thermo Valve Conversion Kit

Reply #8 – July 11, 2018, 12:23:50 am

The cost was $695 if you pick it up yourself. $725 if K&M picks it up. The cost for installation was $200. Someone else on this forum said the savings in fuel paid for it in time. Installation time without interruptions would take a couple of hours. They had to drain coolant to the top of the radiator, but it was saved and put back in.
Cost to replace with electronic (Danfoss) unit was $925 if I recall correctly. I've lost faith in them, however, and decided to go with the simpler mechanical devise that seems more bullet proof.

Re: Thermo Valve Conversion Kit

Reply #9 – July 11, 2018, 12:30:41 am

Quote from: AC7880 – July 10, 2018, 10:10:13 pm

Since welding is involved, do both house and chassis batteries have to be disconnected?

Our house batteries are buried and not easy to get to. As full-timers we have to empty a half bay and remove a panel to get to the house batteries.

I have considered doing this conversion. How do costs compare to replacing the existing system of the 2 speed electronic switch?

I believe the line has to be removed to do the welding as liquid in the line would interfere.

Re: Thermo Valve Conversion Kit

Reply #10 – July 11, 2018, 12:37:20 am

Bob, on our coach, fans don't run when first started, eng cold.

Re: Thermo Valve Conversion Kit

Reply #11 – July 11, 2018, 12:43:19 am

Quote from: Caflashbob – July 10, 2018, 10:25:18 pm

Our 97's dynamatic piloted wax capsule fan temp system goes from a "idle" fan speed not off. My understanding is that is because of the intercooler/radiator/trans cooler needing some airflow across it to cool it?

Was not aware of a off on cold startup fan controller. Electric fan was low/high. Not off to the best of my info?

Bet it does spin cold?

There is a flange adapter with a pin size hole in it that comes with the unit that attaches between the hose and valve. When I asked about it, since the orifice was much smaller than the 1/8" (estimate) one it attached to, I was told that it was for the A/C condenser which is usually mounted on the radiator. My condenser is on the opposite side and has its own fan, so it wasn't needed. Without the adaptor, my fan should not spin (if I understand correctly) until the thermostat opens. If I were to put in a 190 degree thermostat (as opposed to the 180), it should save me that much more by delaying the fuel robbing fan motors by 10 degrees.

Back to the adapter: I would have to fathom why the small hole would allow the fan to spin slowly and the larger hole not at all.

Re: Thermo Valve Conversion Kit

Reply #12 – July 11, 2018, 12:47:40 am

Quote from: rbark – July 11, 2018, 12:37:20 am

Bob, on our coach, fans don't run when first started, eng cold.

That is an interesting point Richard, since we started up four of our coaches at the Pendleton rally in order to compare the fan speed on each at cold idle. Richard's was the only fan(s) that did not move. One other coach ran at the same speed that mine did while the fourth ran at high. This might be a reflection on how many of our coach fans are operating as originally intended.
Incidentally, Richard was the one that told me about the 190 degree thermostat I mentioned in my previous post.

Re: Thermo Valve Conversion Kit

Reply #13 – July 11, 2018, 12:56:04 am

Is Richards controller electric., versus hydraulic?

My Cummins shop foreman called me long ago and said he could not test the low/high fan controller as mine had the variable speed drive.

Not off. Low/high. Sounds like Richard controller if electric might be bad?

Std Foretravel dynamatic controller was full on at 180. All Other brands were 199.

Re: Thermo Valve Conversion Kit

Reply #14 – July 11, 2018, 06:28:46 am

When we replaced our controller our temps ran between 180-190 with a new 180 degree thermostat and radiator. After installing the missing transmission cooler flow orifice we rarely exceed 180 degrees.

Re: Thermo Valve Conversion Kit

Reply #15 – July 11, 2018, 09:48:39 am

Quote from: Wattalife54 – July 11, 2018, 06:28:46 am

When we replaced our controller our temps ran between 180-190 with a new 180 degree thermostat and radiator. After installing the missing transmission cooler flow orifice we rarely exceed 180 degrees.

I keep seeing references to an orifice. Can you tell me where it is located and what it looks like? Is there a functional way of determining that it is missing? My transmission temps closely resemble the coolant temps and often a little lower. On long descents, I might have to down shift to keep RPMs up to prevent transmission oil going over 220 (I know this is well within tolerances).

Re: Thermo Valve Conversion Kit

Reply #16 – July 11, 2018, 11:35:38 am

Sven,
You have the ISM-450. Other than electronics I don't believe there is a significant difference from the M11. It should be directly below the thermostat housing, in the pump to thermostat housing hose. It can be accessed after the thermostat housing is removed.
BTW- the small hose connection at the right inside corner of the radiator, above the cooling water outlet, is the cooling source for the transmission cooler when the thermostat is closed. It will not provide adequate flow if the orifice is missing.

Bob

Re: Thermo Valve Conversion Kit

Reply #17 – July 11, 2018, 07:38:28 pm

Bob, I will test mine after start up tomorrow and see at what temp the fans start spinning. Don't think my controller is bad or I would be overheating. Like Sven stated, there was 4 coaches that we checked. My fans didn't run after starting, 2 ran at low speed and 1 ran at high speed. Under normal driving conditions my cooling temps vary from 180 +/- to 190 +/-. Today was no different with ambient temps in the high 90s.

Re: Thermo Valve Conversion Kit

Reply #18 – July 12, 2018, 09:48:06 pm

Our 99 U270 (Cummins ISC) has the wax capsule fan controller, and I believe earlier Cummins 8.3's did also.

Re: Thermo Valve Conversion Kit

Reply #19 – July 12, 2018, 11:24:26 pm

Quote from: Dave Katsuki – July 12, 2018, 09:48:06 pm

Our 99 U270 (Cummins ISC) has the wax capsule fan controller, and I believe earlier Cummins 8.3's did also.

Yep. Sounds like the solution discussed is to replace failed electronic fan speed controllers. Wax capsule controllers are available in a huge range of temperature selections, a common complaint is that the stock Foretravel installation brings high fan speed on at too low a temp. Swapping the wax controller for one with different temp setpoints fixes this but it ain't cheap.

Re: Thermo Valve Conversion Kit

Reply #20 – July 13, 2018, 01:51:43 am

Found my 199 degree dynamatic controller on the internet from its part number in a google search for $300 from a beaver owner who had a spare by accident.

Re: Thermo Valve Conversion Kit

Reply #21 – July 13, 2018, 08:14:10 am

Quote from: Sven and Kristi – July 10, 2018, 10:02:14 pm

This is what I understand: The valve takes the place of the 2 speed electronic switch which receives input from the CPU through wiring. The pilot valve (to keep things short) is screwed into the downflow pipe from the thermostat via a "weld flange" that was welded over a hole that is drilled into the pipe. The hoses that were attached to the old valve (behind the old switch) are attached to the provided flanges. How it functions: The copper colored probe (see photo) picks up the heat from the coolant flow and causes the wax to expand, opening the lines to the hydraulic fans, allowing coolant to flow, causing fans to turn. When the engine coolant is cold that "bypass" is closed and the fans don't turn until "needed". The speed of the fans are proportional to the temp of the coolant. If someone has a more accurate explanation, I appreciate better info. What I have was explained to me by the mechanic who installed it.
The manufacturer is Dynamic Limited UK and the part is made in Swindon, England. TVCK-101 "Thermo Valve Conversion Kit". In the photo, the valve is on my hitch receiver. I had it mounted inconspicuously near the radiator where the original hoses could be attached.
I bought the kit from Source Engineering in Eugene, OR and K&M Mobile RV Repair up the road in Junction City installed it. Despite the name, the installer has a large professional looking shop. Most of their experience has been with Country Coach. The guys liked my Foretravel.

Source Engineering Inc | Custom RV Chassis | Eugene, OR

Re: Thermo Valve Conversion Kit

Reply #22 – July 13, 2018, 11:00:25 am

Taking source engineering's info about the locked on high speed from having an incorrect hydraulic or a failed electric fan temp controller disadvantages the replacement seems required?

Power and mpg loss are noticeable. System wear is expensive.

Minus 65hp matches the cat literature

Re: Thermo Valve Conversion Kit

Reply #23 – July 13, 2018, 11:53:35 am

I've noticed quicker response from the engine and a significant increase in MPG in my trip from Eugene to Monterey (present location). My main reason for the switch was temperature contro and that was accomplished.
I'll report back at the end of the trip when I have more miles behind me.

Re: Thermo Valve Conversion Kit

Reply #24 – July 13, 2018, 02:11:25 pm

Impressive. Do you and Bob have the same wax capsule controller now? IIRC, Bob's is a fully open at 199 degree model. Some part numbers would be great for both controllers if it's not too much trouble.

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