House Calls with the RV Doctor
By Gary Bunzer
September 2007
Dear RV Doctor:
I own a 36-foot Holiday Rambler Ambassador. The day before we left on our last trip, the temperature here dipped to about 16 degrees Fahrenheit, so I kept the heater on in the coach and placed a small space heater in the bay where all the water lines are.
The morning we left, all was fine. I didn’t see any sign of freezing so away we went. When we stopped about six hours into the trip, I noticed ice forming underneath the bay where the water lines are (I have no way of heating the bay while traveling). Also, we had no water pressure inside the coach. When we stopped about three hours later, the water pressure had returned and everything looked thawed.
Upon arrival at our destination, I did a more detailed inspection and found that the strainer basket part of the water pump had separated slightly from the water pump, which caused a small leak. There was no damage to it so I simply reinstalled the part, and this resolved the leaks. The rest of the trip was uneventful.
When we returned I began to re-winterize the RV using a nontoxic RV antifreeze. I disconnect the supply line from the pump and use a tube in the bottle of antifreeze, allowing the pump to pull the antifreeze into the water lines of the coach. Then I turn on each faucet until the pink stuff comes out. Before any of that, of course, the first thing I do is after draining the water from the system and water heater is put the water heater in the bypass mode. After putting it in the bypass mode, I noticed that the pump pulled all of the antifreeze out of the bottle before shutting off, so I checked to see whether any of the faucets were in the open position; they were not. When I walked around to the other side of the coach, I saw the antifreeze running out of the water heater (the drain plug was still out). My question is, do these valves go bad? I disconnected the lines from the valve and used a flashlight to look into the valve as I turned it from normal to bypass. It seemed to be working fine, but for some reason the antifreeze just kept going into the water heater. Can you tell me what may have happened? Did the freeze somehow affect this? As far as I could tell, we never had anything freezing inside the coach.
James McAdam
Northeast, Tennessee
RV Doctor: James, you certainly have the correct procedure down for traveling and winterizing during cold weather. I’m happy to hear you were able to enjoy your destination, at least, event-free. As for the bypass system, some plastic valves used in a few bypass kits can be prone to early demise due to the effects of cold and heat. I’ve not heard of any problems with brass valves in such applications, but the plastic ones worry me. It’s plausible that the cold and heat extremes have damaged the seals inside the valves, thereby rendering them inoperable. Warping or distorting of the plastic valve body also may contribute to a faulty valve. Perhaps, even, a bit of dirt or hard calcium particle migrated through the system into the valve and damaged the seal. If your bypass valves are indeed made of plastic (I’m not sure which type Holiday Rambler uses), I would strongly suggest you replace them with brass valves. This should prevent the same thing from happening again. Another possibility, though I doubt it occurred, is that the valves were not fully closed during your re-winterization. You appear to be acutely aware of the process, so I would put my money on faulty valves.
Vexing Vent Replacement
Dear RV Doctor:
I just purchased a replacement power vent for the bathroom of my rubber-roofed type A motorhome. I’m handy with tools and want to replace it myself. I know there is extra sealant around the existing exterior flange. The existing vent is a fan type also, so I won’t have to run power. I’m concerned about the sealant, and I sure don’t want to damage the rubber roof while trying to get the old vent off. I know I need butyl putty tape and screws. Could you walk me through the procedure?
Richard Craig
Middleburg, Pennsylvania
RV Doctor: Richard, when working with anything attached to the rubber roof, it’s paramount that the sealant you use be applicable and compatible with EPDM roofing. Any well-stocked RV supply store will have the correct sealant. I do recommend using Eternabond under the flanges of the new vent. But first, to remove the old vent, you’ll need to dig around each mounting screw to expose the head. Using a reversible drill or screw gun, remove all the mounting screws. You can gain access to the 12-volt wires from inside the RV by removing the garnish trim. You should be able to readily see the electrical connections for the hot and ground wires.
After the screws and wires have been removed and disconnected, use a wide-blade putty knife to loosen the sealant under the flange of the vent assembly. Carefully cut through the sealant and remove the vent assembly. Take care not to tear into the rubber membrane itself. Clean off all residue of the old sealant and apply the Eternabond tape directly to the underneath portions of the new vent flange.
The 14-inch opening in the roof should be just right for any aftermarket vent unless the old vent had radiused corners. If so, it will be necessary to cut each corner square with a jigsaw.
After securing the new vent, use Eternabond tape or EPDM-approved butyl caulk to seal around the screw heads and vent edges. Inside, simply hook up the wires as they were on the old vent, reinstall the garnish trim, and you’re set. Remember, not all roof sealants are compatible with EPDM rubber roofing, so it’s important to use the correct type of caulk.