A problem that can occure with excess pressure pumps is when you have 'dirty' fire water, e.g. from a lake. The fine sediment from the lake water use here is clogging up the pressure switches. This in turn is causing the excess pressure pumps to run when not needed. This has been a continuous problem causing plenty of maintenance problems. A heads up for any future design.
Excess pressure pumps are quite common in Canada. Cheers, Kevin Mowle Bruce Power. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Sunday, June 28, 2009 8:10 PM To: [email protected] Subject: *** Detected as Spam *** Re: mercoid switch on wet riser Excess pressure pump. The definitive solution where someone in the range of AHJ's takes stopping false alarms due to pressure surges. I do mean stopping, not reducing. Required in Vancouver (and the rest of B.C.?). Seems New Zealand is on the list. Can be done without the Gamewell (ADT?) unit. Not required to be listed for fire protection service, unless unit also act as the switch for the fire alarm system interface. Yours, Bruce Verhei ----- Original Message ----- From: "Tom Duross" <[email protected]> To: [email protected] Sent: Sunday, June 28, 2009 7:51:04 AM GMT -08:00 US/Canada Pacific Subject: RE: mercoid switch on wet riser What Todd said. They probably replaced the original compound type with a mercury one. >From what I know, Gamewell isn't making them anymore. I think they >ceased last summer, I drove out to get a diff. switch and they told me. Just as an aside, my grandfather is on the patent for this and a few other things Gamewell made before and after the depression when they were in Newton, MA. I have a beautiful one I "kept" in my basement along with a couple of those McCullough type switches I posted about last summer too in really nice shape. Of course, nothing official but my Dad has a picture of him and the crew taken in the shop after another patent was awarded. Funny coincidence. :) TD Go Red Sox! The old Gamewell excess pressure pumps had a very homemade look about them. And that sounds like what is being described. Used to be required in Canada and parts of Europe don't know if they still are.. Richard Sounds like an excess pressure pump. These were used in areas with a lot of pressure fluctuations to prevent false alarms. This was before flow switches with delays. Gamewell was famous for these but Firematic made a fairly simple version of the same thing. Some towns (at least in this part of the world) required them At 11:38 AM 6/27/2009, you wrote: >I saw something which I do not understand and hope someone can explain >this to me. >A 35 year old wet system, manifold with 2 alarm valves. There is a >electric flow switch on each riser, I think added recently. >The valves were trimmed with the normal motor gongs, etc. >The system side gauges are piped together between the two risers, with >check valves, a mercoid switch labeled pump switch, and another mecoid >switch labeled alarm switch. On this piping there are 3 check valves >and a small test , presumably for testing. >There is a small pump with 1/2 in inlet from supply side of valve 2, >which discharges into the pressure gauge piping described above. > >What is the purpose of this? Was it standard at one time? > _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) ************************************************************************************************** *** The contents of this email and any attachments *** are confidential and may be privileged. *** They are intended for the named recipient(s) only. *** If this message has been delivered to you in error, please reply to the *** sender to that effect, dont forward the message to anyone *** and delete the message from your computer. *** Thanks for your help, and sorry for the inconvenience. (BP) **************************************************************************************************
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