Webasto thermotop C Installation Instructions Manual - Plumbing Options
Webasto Part Number : 4110310A
Issue No: 02 : 10th November 2010
Matthew Millard
In the interests of continued development, we reserve the right to change
specifications without prior notice
© Webasto Product UK Limited
Marine Comfort
PLUMBING OPTIONS
WATER (Pressurised)
Example 1. Pressurised system with AAV's
This is the most efficient, reliable and robust system and is most suitable for a marine
installation. There is no need for a header tank to be fitted and therefore radiators can be
installed at any height in any position. This is especially useful when installing a system in a
boat with decks on different levels.
The air purging and filling process is very easy and straight forward.
There is no need to top up any header tanks.
To charge the system a 'filling loop' or connection to the vessels pressurised water system is
required. As indicated in the drawing, two ball valves and a non return valve are required so as
to prevent any glycol contamination of the vessels cold water supply.
An expansion tank is connected via a T piece to the return spine close to the circulation pump
return. This tank has inside a rubber bladder that should be delivered pre charged to 3 bar.
In between the above mentioned tank and pump, the 'filling loop' is Teed into the return spine
also, as seen in the diagram.
A pressure gauge is fitted to indicate the system pressure.
When filling this system for the first time proceed as follows.
Pre mix the water / glycol.
Remove one of the vent caps from each radiator, (the threaded boss that holds the bleed screw
on the radiator). One radiator at a time.
Make sure both the valves on each radiator are fully open.
Carefully fill each radiator as much as you can with this pre mixed fluid and replace the
threaded boss on each radiator. Now the system should be almost full.
With the filling loop connected open both the valves on the filling loop pipe and watch the
pressure gauge. Fill to 1 bar (14.5psi). You will probably hear air escaping from the auto air
vents, this is normal.
Now the system is under pressure, open each radiator in turn and bleed any trapped air.
Recharge and repeat as necessary.
Switch on the heater so the pump is circulating and check the pressure gauge and recharge the
water system up to 1 bar if required.
Ensure both the valves on the filling loop are turned OFF when filling has been completed.
DO NOT overcharge the system above 1 BAR (14.5 psi) when cold.
It is normal when the system is up to full operating temperature for the pressure to rise up to 1.5
BAR (21.75psi) ± 5%.
Example 2. Pressurised with AAV's & Spirovent
Exactly the same system as above but with the addition of a Spirovent unit that will remove the
micro bubbles quicker than AAV's alone.
Visit www.butlertechnik.com for more technical information and downloads.
www.butlertechnik.com