Aqua Hot Pump and Fluid Change Observations

[757driver]

First thanks to Dave (Hogdriver) for going first and paving the way for do it yourself project. Your detailed instructions were a great help.

I had a 108 stir pump that was malfunctioning so I bit the bullet and ordered 3 new Buehler pumps from John Carrillo at Heat My RV https://heatmyrv.com/product/buehler...kit-retro-fit/
His prices were some of best I have seen for the pump retrofit.

The included directions were great except for one small error. The instructions refer to using PLX-CTB-250 constant tension clamps on the 1/2” adapter hose but the kit contained PLX-CTB-200 clamps. Evidently these are the proper ones but are very tough to slip over the heater nipples for the stir pump. I found that I had to slip the hose and clamp over the nipple at the same time.

I used a hand pump from Harbor freight to pump the old fluid out of zone 1 and 2 loops and to refill with new fluid. The old fluid that came out was no where near factory original.

30 gallons of distilled water to flush the system is about right to get things running clean. Zone 2 loop holds about 2 gallons of fluid while zone 1 holds 4 gallons. Yours may be slightly different depending on year and model. The boiler tank holds about 6 gallons of fluid.

Found this pink Camco boiler fluid at RV Upgrades for a good price. https://www.rvupgradestore.com/BOILE...-p/88-8020.htm

With the concentration of this fluid I found that mixing it with equal amounts of distilled water yielded a 43% glycol mixture and a freeze point of -24C.

This worked out to less than $5.00 per gallon of fluid as compared to Century green at $20.00 plus.

By filling the loops with fluid first with the drain line open (to prevent the fluid from coming out of the pumps top opening) and then filling the boiler (after zone 1&2 were fully connected) I found very little air in the system and did not have to jumper zone 1&2 pumps to get the air out. The system fired right up and I pumped at most 2-3 cups of fluid into the boiler to make up any shortfall.

Overall very pleased with the whole changeover. The time to accomplish including cleanup after was longer than expected (8 hours) but I was being very thorough and meticulous.

There is a hazardous waste drop off this Saturday so the concentrated used fluid will get dropped off then.

[brobox]

Excellent post Don! That Century fluid is nasty. I have a hard time believing that Aqua Hot is saying it is OK to run the crud in the system. JMO, but I think that is a lot of problems with pumps failing prematurely. Those little pumps were not designed to push "sludge" only clear liquids. Once we are out of warranty, it's our problem. They are now only replacing one pump at a time, "as needed" while under warranty.

[hogdriver]

Glad it worked Don, for about $100 an owner can do this drain, flush, and refill, but it takes all day. An RV shop would want $500-$1000 to do this and most wont even take on the job.

I’m pleased to say after flushing my system and replacing w Camco pink my boiler fluid is still bright pink after 18 mos of use (12 mos fulltime). That Century fluid was coffee brown with lumps after 6 mos.

[757driver]

Originally Posted by hogdriver

Glad it worked Don, for about $100 an owner can do this drain, flush, and refill, but it takes all day. An RV shop would want $500-$1000 to do this and most wont even take on the job.

I’m pleased to say after flushing my system and replacing w Camco pink my boiler fluid is still bright pink after 18 mos of use (12 mos fulltime). That Century fluid was coffee brown with lumps after 6 mos.

Dave,

I agree. For some that ended up with mixed (Camco and Century) boiler fluid the flushing and replacing along with a fuel nozzle and fuel filter was over $1,000.00. I have enough fluid left over (ordered 11 gallons total to get free shipping) that I may drain and refill the boiler in 6 months time.

Thanks again!

[brobox]

Darwin Hathaway's bill on my drain and flush and flush and flush with 4 motors changed was $1,100. He has also said he will no longer due a fluid flush and change.

[lowejug]

Does doing this fluid change allow the aqua system to run better and more efficient? Or is to just get rid of sludge looking coolant?

[hawgguy]

Originally Posted by lowejug

Does doing this fluid change allow the aqua system to run better and more efficient? Or is to just get rid of sludge looking coolant?

Embrace the power of AND.

[brobox]

Originally Posted by lowejug

Does doing this fluid change allow the aqua system to run better and more efficient? Or is to just get rid of sludge looking coolant?

My AH works after getting the sludge out. Before that I only had hot water and zone 3.

[royals1212]

I have the AH 400 LP and of course the bad pumps. I was lucky enough that AH sent me the upgrade kit. If I were to install it again I would go and buy some different constant tension screw type clamp. 757 driver is correct those clamps are a xxxxx. But unlike everyone else my century fluid is clean. When I drained the heater, I strained the fluid through a coffee filter, no sludge. However, I know that within a few years, I will flush and covert to Camco Boiler fluid because it will have reached its life expectancy.

Thanks to all who have shared, their knowledge of how to flush the aquahots

[rogelling]

Great post Don, I actually stopped at Camping World yesterday and bought all the Camco pink they had which was half concentrate and half premix, price about equal. I still need 4 more gallons. I didn't know I would need that much distilled water so I will go get more. Plan to do job and yearly maintenance next week. My Century fluid looks nasty. I also need to replace the Lowe reinforced overflow plastic hose because it turned black already. I have a whole box of constant torque clamps.

The other thing I plan to do is replace the booster pump for the floor loop with the Bosch pump. I didn't read whether you turned that pump on to help flush old fluid and rinse floor loop??

Thanks for your help with Magnum set up while at Quartzsite, working great.

Too bad I didn'tknow about your pump going out. As I mentioned on another thread, a friend with an Allegro Bus had an AH with GRI pumps but serial # was prior to recall, well AH sent him 3 Buhler pumps and install kit for $150, not a bad deal.

[757driver]

Originally Posted by rogelling

Great post Don, I actually stopped at Camping World yesterday and bought all the Camco pink they had which was half concentrate and half premix, price about equal. I still need 4 more gallons. I didn't know I would need that much distilled water so I will go get more. Plan to do job and yearly maintenance next week. My Century fluid looks nasty. I also need to replace the Lowe reinforced overflow plastic hose because it turned black already. I have a whole box of constant torque clamps.

The other thing I plan to do is replace the booster pump for the floor loop with the Bosch pump. I didn't read whether you turned that pump on to help flush old fluid and rinse floor loop??

Thanks for your help with Magnum set up while at Quartzsite, working great.

Too bad I didn'tknow about your pump going out. As I mentioned on another thread, a friend with an Allegro Bus had an AH with GRI pumps but serial # was prior to recall, well AH sent him 3 Buhler pumps and install kit for $150, not a bad deal.

Roger,

Thanks. No, I did not turn on the floor booster pump to flush the system, the fluid will push through without it being on.

[hawgguy]

Originally Posted by rogelling

The other thing I plan to do is replace the booster pump for the floor loop with the Bosch pump. I didn't read whether you turned that pump on to help flush old fluid and rinse floor loop??

I did on mine. Powered it with a battery from my cordless drill.

[Hondo2015]

Beings this thread appears to be most of us Classics, I have a question about the orange supply piping. While changing out my shocks I noticed the Aqua Hot supply piping is run inside the C channel of the frame Ty-rapped with other wiring with no insulation at all. The route appears to be running from the bedroom register all the way to the dash register. Our registers have never really worked that well so we only use them for PM routine we're supposed to be doing.
So I'm thinking about insulating the lines with the household pipe wrap, anyone have an opinion on this?
Has anyone noticed the same problem?

Thanks!

Jim
Hondo2015
2014 DEQ Aspire

[brobox]

Jim, I can only express my experience. The elbow in the left front wheel was plugged solid. It wasn't slow flow, I didn't have any. I doubt if insulation will do much good, the anti freeze protection is around 43 below, so no chance of freezing and basement heat to stop the water lines from freezing will do the same thing as insulation.

With a 2014, it might be time to check the anti freeze level using a refractometer as stated in the owners manual. https://www.amazon.com/Refractometer...70_&dpSrc=srch

If your original fluid is dark colored , or chunky, it's time to change it. JMO, but the "sludge" slows the flow rate down which would lower heat rate. It's only my experience but none of the companies involved have tested for a different opinion. That was the professional opinion I had from JG labs that did the testing of my fluid.