motorhomeninja Posted March 2, 2018 Share Posted March 2, 2018 I have a 17 plate Roller Team 747, it has some really good design features but the position of the Truma heating dump solenoid is definitely not one of them. Real shame it was not put in alongside the habitation water pump which has easy access. Another one of those design decisions where a component that will need to be accessed has had little thought put in to it's placement. It is positioned under one of the dinette seats but completely hidden by the heating air pipes and every time I try to get to it one of the air pipes flies out of the heat exchanger as it's a tight fit into the toothed connection. Could one of the technical types explain how the dump valve system works with regard to sensing temperature and opening. Link to comment Share on other sites More sharing options...
bolero boy Posted March 2, 2018 Share Posted March 2, 2018 Firstly, if the dump valve is under a heating pipe, and you have the heating on because it's cold. surely the dump valve won't open while your in the van....which is a good thing..... However, if you need to reset it following a post drain down cold spell and you are looking to fill proper to going away or arriving on site, the location might be a hinderance, as you say. If it's a Truma combi hot air systen, Is it possible to move the heating pipe a few inches to get better access? The pipes can be 'stretched' a little to provide some slack....worth a look perhaps. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 2, 2018 Share Posted March 2, 2018 I assume you are referring to Truma’s “FrostControl” safety/drain valve as shown here https://www.leisureshopdirect.com/caravan-accessories/temporary/truma-release-valve-kit Unlike its electrically-operated predecessor, the FrostControl valve’s operation is purely mechanical (though an electric heater can be added to it). Somewhere in the dark recesses of the internet there is (or was) a French motorhome forum in which a motorcaravanner advised on how to ’tweak’ a FrostControl valve so that it opened at a lower temperature (or did not open at all). The modification procedure involved opening the valve up and playing about with the mechanism inside. There were photos showing the valve’s guts and (if I remember correctly) there is a little tube containing a temperature-sensitive wax that is used to trigger the valve’s opening when the air temperature near the valve drops to around 4 degress Centigrade. The principle is similar to that used to open greenhouse roof-vents in hot weather, except the FrostControl opens in cold weather. Link to comment Share on other sites More sharing options...
colin Posted March 2, 2018 Share Posted March 2, 2018 motorhomeninja - 2018-03-02 8:43 AM Real shame it was not put in alongside the habitation water pump which has easy access. Another one of those design decisions where a component that will need to be accessed has had little thought put in to it's placement. It is positioned under one of the dinette seats but completely hidden by the heating air pipes and every time I try to get to it one of the air pipes flies out of the heat exchanger as it's a tight fit into the toothed connection. The purpose of the dump valve is to protect the Truma heater, that's why it's right next to that, as you say unfortunately this can lead to problems with manually operating them. I recall a Rimor we hired being a PITA to operate the valve. As above, moving the air pipe is probably the easiest option, if you wanted to move the valve it should still be close to Truma and will require a hole directly below it. another option might be as our Globecar which has a opening cut throu a panel right next to valve. Link to comment Share on other sites More sharing options...
motorhomeninja Posted March 2, 2018 Author Share Posted March 2, 2018 Many thanks Derek for answering the question on how it works, I wondered whether it was controlled electrically and there was a thermostat in the van. The current weather has highlighted the problem! The other issue with the position of this valve is that it is over a vent through the floor so all the cold air is drifting up over it? I am very tempted to move it, but don't want to invalidate any warranty. Second option is to make an access hole in the bottom of the dinette seat so I can get to it without removing dog cage and cushions. Link to comment Share on other sites More sharing options...
witzend Posted March 2, 2018 Share Posted March 2, 2018 If You decide to fit a manual one heres a better option https://www.ebay.co.uk/itm/TRUMA-ULTRASTORE-WATER-HEATER-BOILER-ABO-SAFETY-DRAIN-VALVE-70141-02/372191240060?epid=1205390427&hash=item56a8539f7c:g:n60AAOSwndZaV1If Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 2, 2018 Share Posted March 2, 2018 Graham As Colin has said, the purpose of the Truma safety-drain valve is to protect the heating appliance from frost-damage in cold weather by automatically emptying the appliance’s water resrvoir. To allow this to happen the valve needs to be close to the heater and at a relative height that will permit the heater to drain. Truma’s installation instructions for the FrostControl valve can be read on Page 17 of this document https://dealernew.truma.com/_anweisungen/Truma_Katalog/pdf_verzeichnis/30_000/34030_11800.pdf The instructions say "The FrostControl must be installed in the immediate vicinity of the unit in the heated room in a location that is easily accessible to the user. Make sure that rotary switch and push-button can still be operated. When selecting a location, please ensure that the FrostControl is not installed in the vicinity of external heat sources (e.g. power supplies) or in the immediate proximity of warm air ducts.” but motohome manufacturers often seem oblivious to Truma’s instructions for installing the heater, never mind the drain valve. I’m not sure how to interpret your comment “...every time I try to get to it one of the air pipes flies out of the heat exchanger as it's a tight fit into the toothed connection”. Each of the four plastic hot-air outlets of a Truma “Combi” heater carries a small hole through which a short self-tapping screw can be inserted, ensuring that the flexible ‘trunks’ that distribute warmed air around the motorhome will not become detached from the heater. Other components (eg. elbows, T-pieces, Y-pieces, couplings) into which air-trunks push also carry holes that can accept ‘tethering’ screws as shown in the attached photo. So if you are finding that moving an air-trunk causes it to detach and/or you follow bolero boy’s suggestion to ’stretch’ the trunking to improve access, using tethering screws would be sensible. Plainly, if there’s a through-floor vent to the outside air by your FrostControl valve, this will tend to cause the valve to open earlier than if there were no vent. Presumably this is a gas ‘drop vent’ which, if sited close to a Truma “Combi” heater, is (in my view) a daft idea. Whether it’s worth you cutting an access hole in the seat base will depend on how much of an irritation the present arrangement is. My Rapido’s FrostControl valve is buried beneath the bed and a covering panel needs to be removed to reach it. Raising the bed and removing the cover takes about a minute and, as I don’t need to get at the valve often, that’s OK. If accessing the valve involved considerably more effort I’d be considering doing something about it. Link to comment Share on other sites More sharing options...
monique.hubrechtsgm Posted March 2, 2018 Share Posted March 2, 2018 A pain in the... for all motorhomers. nobody cant find the side reset button in most cases at winter time. some drop already at 8 degrees temp. There you go on a site to get a refill in cold temp. Keep your boiler hot. Link to comment Share on other sites More sharing options...
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