Descaling toilet pipes
Loo-pipe scale is something out of sight and generally out of mind. But we ignore it at our peril. Richard Hare suggests a way to clear it
Loo pipe scale may be out of sight but ignore it at your peril!
Not everyone with a sea loo is going to have a problem with uric scale accumulation, this being the hard crud that accumulates in loo pipes and ultimately blocks them.
Those of us who sail in fresh water will be significantly less affected. Also less affected will be those that flush plenty of water through the pipes after the loo has been used. This reduces the amount of uric acid sitting in the pipes. Keeping pipe runs short helps too.
Uric scale accumulation is caused by the reaction of uric crystals – those same critters that conspire to give us gout – and calcium traces in the water that we pump through our systems. Salinity exacerbates the problem.
Pipework most affected is that below the waterline. It’s here, at the ‘wet’ end of the system, where the lethal cocktail accumulates and is at its richest. Fast falling ‘dry’ pipework is less affected but the scale in this case is harder and more difficult to remove.
The significance of this is that our loo pipes could be half the diameter we believe them to be, or worse… Having seen how much accumulated in eight
years I have taken care to stay on top of the problem, usually once a year.
How to descale
The boat needs to be out of the water for descaling to be effective. Using vinegar, 36 hours might well be sufficient time but when using LeeScale at 20% with water this time can be brought down to 7-8 hours. Leaving it in longer does no harm.
To work out how much solution will be needed we must first measure the length of pipe we plan to treat. Given that 1lt of fluid fills 0.75m of normal loo outlet pipe, 4lt was ample to dose Keppel’s below waterline system, it being short and entirely confined within the heads. The holding tank is instrumental in this procedure as it enables the descaler to be poured directly down the system without airlock complications.
I did the dosing in two sessions as I was unsure that the delicate valves in the Jabsco loo pump would cope well with the pressure of pumping so much descaler round in one go. See far right, opposite page for the procedure on descaling the whole system in one hit.
I used malt vinegar, that’s standard 5% acetic acid vinegar that we put on our chips. Great on cockles too:
Stage 1
1 Flush two buckets of fresh water through the system from toilet pan to seacock to make the job less unpleasant when the joker valve is eased away behind the toilet pump.
2 Slacken the joker valve connector. Allow the (now) clean water within the hose to fall out. Slackened as such this prevents an airlock and it enables the descaler to spread evenly across the lower part of the system.
3 Close outlet seacock to trap the descaler in the lower system.
4 Open the valve below the holding tank. 5 Pour descaler in through the holding tank pump-out deck fitting. Via the holding tank the descaler drops to the lowest point and back-fills the pipe leading up to the diverter valve.
6 Now tighten the joker valve connector to close the air release. The holding tank now provides this function.
7 After 48 hours, drop the jollop out of the boat by opening the loo outlet seacock. If necessary open the pump-out deck fitting to ensure no airlock.
8 I opted not to flush through with clean water, as vinegar traces could do no harm and might even be a benefit.
9 Discard the vinegar – you won’t be wanting to use it accidentally on your fish and chips!
Stage 2
Also containing seawater, the uphill length of hose from the loo pump to the highest point of the system needs to be descaled, although it ought to be less affected than the lower part of the system. Why? Generous pumping after use should remove almost all of the urine. So, with the loo bowl and the pipe above it empty, proceed as follows… 1 Based on a ratio of 1lt of descaler to 0.75m of pipe I pour 1lt of descaler in the loo bowl. 2 Ensure the diverter valve is directing the flow to the outlet seacock and open the seacock to free up the airlock. 3 Pump descaler from the bowl into the pipe until you hear it falling down out of the boat. 4 Leave descaler in the pipe for 48 hours. 5 Fill the bowl with fresh water and pump both it and the now foul descaler out of the boat. 6 Crack open the joker valve clamp if the pipe is to be emptied.
Descaling in one hit
The descaling of the complete system might possibly be done in one hit, thereby reducing the time it takes by half. A caution though – anyone who has accidentally over-pumped a loo pump when the seacock has been closed will know that some repair work might be needed on the pump mechanism. It occurs to me that the one hit method might possibly lead to this, especially so if long runs with lots of liquid is involved. Me? I prefer not to take the risk.
However, if time constraints leave this as the only option then give it a go, just pump gently:
1 Perform stages 1-4 described in Phase 1 opposite page
2 Fill bowl with 6lt of descaler, ie sufficient in this case study.
3 Pump descaler down to the closed outlet seacock. It will find its level as the tank breather functions as a pressure release.
4 After 48 hours, drop the jollop out of the lower part of the boat by opening the loo outlet seacock. If necessary open the pump-out deck fitting to ensure no airlock. 5 Fill the toilet bowl with fresh water and pump out the descaler in the pipe that runs from behind the loo up to the highest point in the system.
6 Discard the old vinegar.
Cost: 10 x 0.5lt bottles of Co-op malt vinegar @ 49p/bottle = £4.90