Prevost Gurus - the Member Funded Prevost Forum
Engine heat loop from AquaHot - Printable Version

+- Prevost Gurus - the Member Funded Prevost Forum (http://www.prevostgurus.com)
+-- Forum: Discussions (/forumdisplay.php?fid=25)
+--- Forum: HVAC (/forumdisplay.php?fid=34)
+--- Thread: Engine heat loop from AquaHot (/showthread.php?tid=821)

Engine heat loop from AquaHot - Jusfine - 01-02-2017 14:28

Hi Group,
I have 97XL Royale and seem that I can't pre heat engine block from the exchanger switch on the dash. It lights up when pressed, but after hours being on the block still isn't warm at all.

I have no idea if a pump is used to move coolant thru block, where the pump is located, or if there is a fuse or breaker somewhere.
It has worked up till 3 weeks ago.

Thanks for your help
Jonathan Fine
1997 Royale XL # 201

RE: Engine heat loop from AquaHot - cmillsap - 01-02-2017 18:16

(01-02-2017 14:28)Jusfine Wrote:  Hi Group,
I have 97XL Royale and seem that I can't pre heat engine block from the exchanger switch on the dash. It lights up when pressed, but after hours being on the block still isn't warm at all.

I have no idea if a pump is used to move coolant thru block, where the pump is located, or if there is a fuse or breaker somewhere.
It has worked up till 3 weeks ago.

Thanks for your help
Jonathan Fine
1997 Royale XL # 201
Do you have a Wabasto or AquaHot? Is it running ok but not producing hot water/coolant going to the engine? The circulation pump should be internal to the unit. Did someone turn off the valve on the block heater hose loop near the engine?

RE: Engine heat loop from AquaHot - Jusfine - 01-02-2017 19:55

Hi Chuck
Thanks for your response. I found the pump for the engine loop. Checked the fuse, the pump was humming,
seem that there is something sticking in the DD thermostat. After a few taps on the housing I have coolant flow.
I will turn it on tmro morn and see if it is still able to warm the block...but a thermostat is in my future.
Chuck you still have all those BB's??? Thank you.
Jonathan Fine
Aztec, NM soon to be in Quartzsite.

RE: Engine heat loop from AquaHot - davidbrady - 01-02-2017 20:29

Hi Jonathon,

Below I attached the AHE-100-02S Service manual. Page 27 has troubleshooting steps for the engine loop heating function. As you've already discovered fuse 'A' is the fuse for the engine loop pump. The manual goes on to explain the procedure to replace the pump brushes, they often go bad. I don't think the DD Series-60 thermostats come into play. When the DD t-stats are closed the DD water pump circulates coolant thru the head which is where the AH taps in, so there is a fluid path even with the t-stats closed. But, my New Year resolution is to kick my caffeine habit so bear with what may be my fuzzy logic! LOL!

RE: Engine heat loop from AquaHot - cmillsap - 01-03-2017 14:14

Jonathon,

FYI. In the S-60, there are two thermostats sitting side by side in the thermostat housing to provide redundancy.