deciphering honeywell vaportrol model numbers

archibald tuttle

cal me a traditionalist or hidebound, but I don't feel i'm getting sufficient responsiveness form the physically switched 16 oz. vaptrols so i'm trying to go back down memory lane to find some old ones with liquid metal bulb switching that are still finnicky in those low pressure ranges but don't seem to have the same threshold difficulties for kicking in and out. the new ones seem to overrun and then fail to kick back in even if you set the differential to virtually nothing.

so the ones i'm running with success are L608A1406

I've found L408B1081 on line which seem to similar operating specs. it does have thicker reaction chamber although about the same diameter and it is a 0-16 oz. control with subtractive differential.

what i'm worried about is that some of these were apparently made as NO controls with no NC contacts. So a fall in pressure will break a circuit rather than make one.

now, i guess i could use a solid state relay with NC terminals that breaks on signal, then when the vaportrol breaks on fall the relay returns to unenergized state and as long as I'm wired to NC terminals it would call the boiler.

But if I understood what those numbers and letters actually stand for, maybe i would know what i was getting. a lot of these are dusty boxs, never used but know nothing about them auctions. Some say they are for 16 oz controls but it turns out that that is the range of adjustment for the differential and they are 4lbs controls, etc.

calling all old catalogue nerds.

thanks,

brian

archibald tuttle

in the answering my own question department, found a nice chart at controlscentral.com. can't really figure out why the last 4 digits aren't consistent with functions between the L408 line and the L 608 line but this tells you more or less what you need to know.

L408A1132 0 oz/in2 to 16 oz/in2 2 oz/in2 to 16 oz/in2 Auto recycle SPST break on pressure rise Siphon Loop

L408A1157 0-4 psi 2 oz/in2 to 16 oz/in2 Auto recycle SPST break on pressure rise Siphon Loop

L408B1131 0 oz/in2 to 16 oz/in2 2 oz/in2 to 16 oz/in2 Auto recycle SPST break on pressure rise Siphon Loop

L408B1149 0-4 psi 4 oz/in2 to 16 oz/in2 Auto recycle SPST break on pressure rise Siphon Loop

L608A1046 0 oz/in2 to 16 oz/in2 4 oz/in2 to 16 oz/in2 Auto recycle SPST break R-B, make R-W on pressure rise Siphon Loop

L608A1053 0-4 psi 4 oz/in2 to 16 oz/in2 Auto recycle SPST break R-B, make R-W on pressure rise Siphon Loop

archibald tuttle

So my one other question is that i see these controls, same model numbers, some with an almost flat diaphragm and som with maybe an inch think kettle for the diaphragm. Much difference there? One stainless steel , one not . . . or ?

thanks

Shalom

Try this link: Honeywell Pressure Control & Limit Cross Reference

archibald tuttle

Shalom,

thanks, that is an encyclopedic reference although one has to infer which are mercury switches and which aren't, i.e. those in replaced column.

I was able to cross check that with numbers off some mercury vaporstats i have inservice.

But the perhaps the best thing to come of all this was the coalescing of energy on this thread around designing a more responsive alternative using two very accurate and modest cost Dwyer controls with very little hysteresis to supplant the vaportrols with built in differential. (warning about that link: not for the faint of heart or those opposed to threadjacking).

heres my version in the end: