i've looked on the internet and it may be a c402c if it's the new style bench type you can tell the cassette on this one has a retractable handle and wheels to ease emptying. the ones below are the older type you have to carry them. go to thetfords site look for the one you have you then will have the model number then contact thetford 'ask thetford'. put the question to them.
a c2 is electric flush. c3 are mostly in motorhomes and fed from main water tank via a electric none return valve on the toilet. a c4 is a manual pump one unless it's been change to electric.
uk & europe www.thetford-europe.com
australia www.thetford.com.au (even get request from australian campers)
australia site has stockist list.
home page select english {if in australia forget this selection it doesn't come up)
select customer service (top line)
select products from top line
select bulit in or portable which ever applies.
select user information from list on right.
select repair instructions from list on right
select built in or portable which ever applies.
select select your toilet series model number from right list.
you will now be in the pdf listings for your range of toilets just select those that apply to your toilet and down load them they're free.
as you go through watch for 'ask thetford' on left listings
you may not find what you want and you can send them a message.
for safety reasons which i agree with thetford do not offer repair advice for fridges. refer to service centre
Bob
September 2010