rolandrat Posted January 19, 2015 Share Posted January 19, 2015 On page 163 of January's 3 mmm's there's a reference to a damp meter check, that's all well and good if the damp meter that was used has a current up to date calibration certificate. A dealer should be willing to show proof if asked. The true reading can be severely distorted and misleading if the damp meter calibration date has not been adhered to. Link to comment Share on other sites More sharing options...
rolandrat Posted January 19, 2015 Author Share Posted January 19, 2015 The damp meter in question is called a Protimeter PM301 and is supplied by Surveying & Safety Equipment who also carry out the calibration service. Link to comment Share on other sites More sharing options...
Rayjsj Posted January 19, 2015 Share Posted January 19, 2015 I regularly keep a check on mine with one of These : http://www.amazon.co.uk/Brennenstuhl-1298680-MD-Moisture-Detector/dp/B003CSNV2Q/ref=sr_1_1?ie=UTF8&qid=1421700122&sr=8-1&keywords=Damp+meter ok, it's not the 'Best' but it's accurate enough to keep my mind at rest. Ray Link to comment Share on other sites More sharing options...
rolandrat Posted January 20, 2015 Author Share Posted January 20, 2015 Ray, have you owned it long enough to warrant a calibration? I've just got mine back from Survey Express Services based in Addlington south of Stockport with an up to date calibration certificate. Link to comment Share on other sites More sharing options...
mike 202 Posted January 20, 2015 Share Posted January 20, 2015 I have got a damp meter from LIDL and although not costing much it does come with an electronic test cap which you press the two probes onto two pads on the test cap and if all is well the digital display shows 19%. so in effect it is calibrated every time you use it, proved you test with the cap before using it. I still have a professional habitation check and damp test done every year, but I use my LIDL meter for a confidence check during the year. Mike Link to comment Share on other sites More sharing options...
rolandrat Posted January 20, 2015 Author Share Posted January 20, 2015 Mine has a standard test checker that is set at 18% to use before use if necessary but it isn't a calibrator it's just a guide. You will find that the accuracy will vary with time. Link to comment Share on other sites More sharing options...
Tracker Posted January 20, 2015 Share Posted January 20, 2015 It's not an exact science so no need for fancy kit and calibration etc. You just need to know if the internal structure is wet enough to be damaged by a possible leak and potentially in need of structural repair or just condensation stains on the panel and for that purpose any cheap and simple damp meter tester will suffice. Best to air and dry the van internally before testing though as surface condensation and high humidity can distort readings by a far greater margin than variations between meters. If in doubt and worried - maybe buy two different inexpensive meters and compare the readings! Link to comment Share on other sites More sharing options...
rolandrat Posted January 21, 2015 Author Share Posted January 21, 2015 Tracker - 2015-01-20 11:00 PM It's not an exact science so no need for fancy kit and calibration etc. You just need to know if the internal structure is wet enough to be damaged by a possible leak and potentially in need of structural repair or just condensation stains on the panel and for that purpose any cheap and simple damp meter tester will suffice. Best to air and dry the van internally before testing though as surface condensation and high humidity can distort readings by a far greater margin than variations between meters. If in doubt and worried - maybe buy two different inexpensive meters and compare the readings! So what would you say if two dealers got different readings in the same area using an identical damp meter? Link to comment Share on other sites More sharing options...
hallii Posted January 21, 2015 Share Posted January 21, 2015 I would say damp meters are unreliable when used on a motorhome. The cavities behind the walls and roof, aluminium, and foil backed insulation can all give spurious readings. When the inside panels are wet it's to late, much damage can already be done. I use my eyes and fingers and remove panels over cavities. H Link to comment Share on other sites More sharing options...
Tracker Posted January 21, 2015 Share Posted January 21, 2015 rolandrat - 2015-01-21 10:13 AM So what would you say if two dealers got different readings in the same area using an identical damp meter? That one of then is clearly wrong! ALWAYS get your van damp tested before agreeing any deal if selling. It happened to us when selling a van a few years back when two dealers had already found our van dry and a third used very expensive 'repair' costs for the 'damp' they found as an excuse to get out of a show deal. They also refused to accept my own damp meter readings taken at the same time which were in line with the two previous dry checks. We dealt elsewhere and I doubt we will return! Link to comment Share on other sites More sharing options...
rolandrat Posted January 21, 2015 Author Share Posted January 21, 2015 You did right to go elsewhere. I remember some time back it was tried on with me. The salesman did in fact take extra money off me, it could have been more until the service manager pointed out that there was a wiring loom close to where the damp meter had been placed. When we returned home with our new motorhome I rang the manufacturer and told them about the salesman finding damp in our trade in and how much we had to pay extra to complete the deal. It was pointed out that the motorhome was still subject to the manufacturers warranty and would be repaired free of charge. The manufacturer said that they would take it up with the dealer and said that they would send me a cheque for the extra money I had paid. True to their word I received a cheque off them. I will never use that dealer again. Unfortunately there are other similar dealers who try it on. It was because of that lousy experience I bought an up market damp meter which I have calibrated. The manufacturer lets me know when a calibration is due. Link to comment Share on other sites More sharing options...
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