Garden Railway Forum

Anyone know if the Roundhouse Ronson valve will fit a Merlin gas tank? The filler on my Monarch is a pain to fill. I've removed the valve & soaked it for 48 hours in acetone with no improvement. It fills slowly with no clear sign when the tank is full.

It's taken me a long time to get to this!!
I have a defunct Monarch, in process of batterification.
The gas filler has the same thread as Roundhouse.

I tried a valve from evilBuy, desigend to replace RH.
This fitted, but the vent holes appear to be obstructed by the tank body.
Consequently, the fill is unreliable.

You may have more success with a genuine RH valve.

big-ted wrote: ↑Sun Dec 04, 2022 5:53 am Anyone know if the Roundhouse Ronson valve will fit a Merlin gas tank? The filler on my Monarch is a pain to fill. I've removed the valve & soaked it for 48 hours in acetone with no improvement. It fills slowly with no clear sign when the tank is full.

Ronson changed the filler valve design some years ago. Whether a current valve from Roundhouse will work in a Merlin tank will depend on the length of the thread in the tank filler bush.

There is a photo in this thread showing the different valve designs.

https://gardenrails.org/viewtopic.php?f ... on#p104611

As a test, open the burner gas valve when filling the tank so the gas can vent through the gas jet. Regner filler valves work this way. If the tank is now easier to fill, then the Ronson valve vent is blocked. It may be that the original valve has been replaced by a newer one at some time and the thread in the bush is blocking the vent.

Regards,
Graeme

Hmm. Thanks for this Graeme. I'm only just getting to take a close look at the Merlin valve side by side with a new style Roundhouse one.

The Roundhouse one won't fit the Merlin tank. The unthreaded portion of the Roundhouse valve is actually too large that it won't allow the valve to fit into the hole in the Merlin tank. As far as I can tell, this means the Melin must use a smaller thread diameter also.

To be honest I can't for the life of me see a vent hole in the Melin valve. However it does look like the o-ring installed is too large a cord diameter. I've removed the o-ring completely & checked for leaks. The valve function now seems much improved, & no leaks. I won't get to steam the loco for a while but will update when I do. In the meantime, I'll see if I can find some finer o-rings, just in case.

Thanks again.