Replacing Non Return Valve
  1. Undo non return valve (no.10 ) using a 20mm spanner.
  2. Replace with a new non return valve.

There are two reasons why this job may not be that straight forward.

  1. The non return valve snaps off on removal.This can sometimes be fixed with out taking the heater out.
  2. The non return valve is inaccessible due to the water heaters position.The heater may need to be removed.

Water heater removal.

Tools:Philips head screwdriver,20mm,17mm spanners,electrical screwdriver,flat head screwdriver.

For This job you need experience in both gas fitting and 240v wiring please seek professional advise if you don't.

  1. Remove flue cover (No.13)
  2. Remove 8 screws that hold heater housing in.(No. 9)
  3. From inside the van remove the gas joint using a 17mm spanner.
  4. If there is enough slack in the water pipes then the heater can be pushed out from the inside.The sealant on the outside of the van may not let go to start with, so the heater may have to be levered from the outside,be careful not to damage the van panels.If there isn't enough slack, the water pipes will have to disconnected before the heater can be removed.
  5. If you have a GE model then the 240V will have to be disconnected.
  6. If you only need to change the non return valve then it is accessible at this point.Change the valve, reseal the heater with a mastic, Not Silicon Sealant, and refit, reversing steps 5) to 1).
  7. For any other reason the heater can be removed.

Snapped Non Return Valves

Tools: Junior hacksaw blade, small ended screwdriver.

  1. This job can be done without removing the heater but it is sometimes easier to do so.
  2. Remove the heater as per above.
  3. Upright heater on the bench with the cast end down.
  4. Cut a groove into the snapped off part of the valve.Be careful not to cut down into the cast threads.
  5. cut a second groove around 3mm away from the first groove.
  6. Leaver the middle section out using a small screwdriver.
  7. The rest of the valve should then collapse into the centre.If it doesn't then another groove may have too be cut.
  8. If you have such a tool then the threads can be cleaned out with an M16 tap.
  9. Fit new valve by slowly screwing it in, be careful not to dethread the valve.
  10. Refit heater.Attach the water pipes outside of the van if you can a test for leaks.

Water Tank Fitting

If you have got a leak from your water tank, then you can fit a replacement.
It needs to be a new tank kit from a Carver stockiest because it has a lip on it to take a new O-ring.

You can't use the old tank because it will have stretched, it also doesn't have the lip.

Tools: All tools for the above jobs.A torque wrench.vegetable oil.

If you have a GE model you will have to fit a GE kit with the element pre fitted.
This will also have to be disconnected and connected, so a knowledge of 240V will be needed.

  1. Remove water heater as above.
  2. Drain all water out.
  3. Undo large nut ontop of the heater and remove the tank.
  4. Unscrew the tie rod ,See diagram.
  5. If pre 1995 fit the correct new tie rod, use nuts provided as a tightener to prevend damage to toe tie rod.
  6. Lubricate new O ring with vegetable oil and seat onto heater.
  7. Place new tank onto heater.
  8. Place small O ring onto tie rid.
  9. Place thick washer onto tie rod with the groved side down.
  10. Fit nut and torque to 15 NM.
  11. Re fit heater and test.

Replacing Over Temperature Valve (Fusible plug)

Tools:A 13mm socket, deep if possible, A philips head screwdriver.

  1. Remove flue cover No. 13
  2. Locate over temperature valve No. 14 and remove.
  3. Check valve by blowing through it,if air passes through it then replace.
  4. Fill water tank and check.

Replacing Pressure Relief Valves

Tools: 20/21mm Spanner/Socket,Pair of grips.

There are two types of Pressure Relief Valves,the old type don't have the quick drain facility,the new quick release valve can be fitted to the older type of heater but the flue cover will have to be replaced to.

  1. Remove old valve No. 12.This may not be as easy as it sounds.The nut part of the valve isn't easy to get to with a spanner.A socket can be used but the valve is too close to the heater housing so you will put pressure on the threads and they may snap. If they do snap then follow steps 4 to 10 in Snapped Non Return Valves.
  2. If the leak is coming from the centre of the valve then you may be able to change the inter of the valve without taking the valve out.
  3. Replace and test.

Replacing Gas Burner Module

Tools: A Philips Head Screwdriver.

This job involves breaking a gas seal,no skill is needed to do this because the joint is made by an O ring that is attached to the module.If you are not confident to do this please see your nearest dealer.

  1. Remove flue cover.
  2. Remove burner cover No. 16.
  3. Insure the gas supply is turned off then release module fixing screws located underneath the solenoid to the right of the module.
  4. Remove the module.
  5. Disconnect the din plug at the rear of the module.
  6. Replace new module.Insure that the fixing screws go into the heater housing with little effort,If they are tight then they may be cross threaded, this may cause the gas seal to not seat correctly and could damage the heater housing.
  7. Test.