Thread: Dry vs. Wet
11-23-1999, 12:45 AM #1pyroknightFirehouse.com Guest
Dry vs. Wet
What does your department do? Dry pump when the temp's below 32 F, or wet? Any problems?
11-23-1999, 12:40 PM #2Bob SnyderFirehouse.com Guest
We go with dry pumps in the winter. On the night we decide to drain them, we post the "pumps are dry" message on the chalk board right inside the engine room door. That lets everyone know to expect dry pumps until spring. Since everybody knows it, there haven't ever been any problems. Besides...ever deal with a frozen pump? It takes forever to thaw and it can do serious damage.
11-23-1999, 03:20 PM #3ChapCaptFirehouse.com Guest
We leave ours wet. I heard that if you leave the pump dry, the packing dries out and causes problems.
Any validity to this? Does it really matter or is it personal preference. (Aside from freezing your pump solid, that I know is a bad thing)
11-24-1999, 08:51 AM #4Bob SnyderFirehouse.com Guest
I can't say for sure whether you can have packing problems from this or not. We've never had problems with packing as a result of running pumps dry. We don't really keep them dry for very long...usually early January through mid-March and, of course, they get used periodically during that time. At minimum, they get wet during the monthly maintenance checks, when we run the pumps, work the transfer and relief valves, and adjust settings, if needed. I don't know if this makes any difference or not.
11-24-1999, 01:20 PM #5SNOWMANFirehouse.com Guest
"Modern" pump packing is made from a graphite based material and doesn't dry out. The packing material relies on the lubricating ability of water to "seal" and prevent the scoring of the pump shaft. You should not RUN your pump dry (no lubrication) but it does not hurt the packing to STORE it dry. BTW, periodic adjustment of the packing is necessary (as it wears) even with the lubrication of the water.
To answer the question posed in this forum, we run wet and dry pumps. The current chief thinks we need to drain the pumps in cold weather but it is really not necessary. The "thermal mass" contained in the pump, and whatever water it contains, will keep it from freezing while traveling to the incident(unless you're going 30 miles!). Once on scene, you need to then circulate water to prevent freezing. I speak from experience, as we frequently have wintertime temps of minus 20 degrees in Montana. We do experience freezing of the "capillary" lines feeding the pressure gauges. Never had lines rupture, but have ruined a couple of gauges. It is really a hassle, as the attack lines continue to operate but you do not know what pressure you are pumping.....that is when we rely on the veteran engineers in the department to run the trucks. They can usually estimate very closely, from experience, what the lines are pumping at. Sorry about rambling on, I'll quit now.
[This message has been edited by SNOWMAN (edited November 24, 1999).]
11-24-1999, 05:18 PM #6AffFirehouse.com Guest
We also run are pumps dry during the winter months. (From abount Nov. until Feb./Mar.) Keeps from having to drain them on the fireground if they are not to be used.
11-27-1999, 03:15 PM #7Capt. CrunchFirehouse.com Guest
We leave ours wet year round,never have had a problem with them freezing.Provided you have a heated apparatus bay.Even with being on scene for a prolonged time,with the heat off the motor and the metal around the pump it self it would keep it warm enough to keep it from freezing.If it looked liked we were going to be out for a long time and it was realy cold out.then we would ingage the pump and pull the tank to pump & fill tank valves to circulate the water through the pump.
However we have had a few incidents that after a long time with the pump ingaged,when
we would try to transfer back to road and the trans would not come out of direct gear.I supose with 10 to 12 feet of trans linkage it's bound to happen.But sometimes after a mile or so the trans would heat up enough to start shifting.It makes for a real interesting trip back to HQ.
Be safe all!!!! Rich
11-28-1999, 12:07 AM #8RVFDCaptFirehouse.com Guest
We have a heat shield for one of our trucks that bounces the heat from the engine onto the pump to keep it from freezing so we, obviously, run this one wet. We have a older engine that we run dry as we are a vollie dept and may travel upwards of 10-20 miles to a scene and we don't want to take a chance of the pump freezing in route. Our newest Pierce ('97 Responder)...we have not had a problem with. We run it wet. The closest paid dept, Huntington WV, which is right across the river I believe runs their's wet but they use kerosene heaters under their pumps on scene if it gets very cold.
11-28-1999, 07:25 PM #9raricciutiFirehouse.com Guest
We run ours wet, but place the pumps in gear when stopped at a scene when the temps are below freezing. Our responses are short (about 6 minutes max.) and it does get pretty cold here in winter (Pittsburgh area). We haven't had any real problems - our newer vehicles have gauge or pump panel heaters on them to further guard aginst freeze-up.
R.A. Ricciuti, Firefighter
Mt. Lebanon Fire Department
12-14-1999, 11:51 PM #10Chief TaylorFirehouse.com Guest
We run wet as well, most of our calls are going to be less than 2 hours if that. If a run is longer than that, we have recirculating valves that keep things warmed up for us.
12-24-1999, 02:54 PM #11DavidjbFirehouse.com Guest
We maintain wet pumps year round. During the winter the pump heaters are left on and the pump to tank and tank to pump valves are left open, and the water is recirculated while on scene.
David Brooks, Firefighter, D/O, 1st Resp.
Newmarket Fire & Rescue
Newmarket, New Hampshire
01-13-2000, 01:14 AM #12pvfr fyrfyterFirehouse.com Guest
on our small town vol. dept. if your arms are cold without a coat the pumps must be recirculating before you leave the station. this goes for all type of units, pumpers, tannkers, grass units. never had a pump freeze even when the wind chill was 25-30 below zero.
01-13-2000, 03:43 PM #13WaynoFirehouse.com Guest
I have the understanding that even if you drain your pumps there is still residual water in there that does not come out (remember HAZ-MAT basic? empty drum? or residue).
Lets say this: If there was infact the residual water and it did freeze. As soon as you start to pump from a supply that ICE (from the sidual water) could break free and damage the pump seriously.
or as I'm told from a pump Mechanic in our area.
I dunno however
We run our pumps wet year round normally our responses are within 5 to 6 miles and on scene time 3 hours or less. But we do practice the same as many above CIRCULATE!!!
Wanted to give my input!
[This message has been edited by Wayno (edited January 13, 2000).]
02-05-2000, 06:31 PM #14wsfiremnFirehouse.com Guest
the way we do it at my department in southern indiana is to leave the pump wet and ith radiator fill open. when we arive on the scean and the pump is not going to be used place the truck in pump and open the tank to pump valve and set the rpms to about 850 or 900 (about 55psion the discharge guage)this will circulate the water from the tank through the pump. on newer trucks do the same but most have a recirculate/tank fill handle open this with the tank to pump valve and you will have no problems on freezing.
capt. todd atherton
natfd eng co 44
02-06-2000, 04:17 PM #15G KoonsFirehouse.com Guest
We leave the pump wet year round. For 15 years we drained the pump and have experianced pump packing problems (leather packing) The truck is in a heated garage. We are rural and sometimes have a 5 mile run. Never had a pump freezing on the way. Also we open the tank to pump valve before we leave the station to help prime the pump for booster tank operations.Our SOP for winter operation is at a scene if not in a pump operation we place the pump in gear and circulate water by means of the tank refill valve.
04-19-2000, 11:50 AM #16Ward WatsonFirehouse.com Guest
We leave ours wet. The only time we really worry about this is if the temperature outside is going to be below 20-30 degrees for several days. I believe in leaving them wet and circulating the water, but that's just my opinion. Hope this helps.
05-02-2000, 09:21 AM #17goshen392Firehouse.com Guest
You can run your pumps dry if you still have graphite packing in your pumps. If you have a new pump with a mechanical seal you cannot run dry because you will damage the seal. The seal must remain wet to retain its capability to seal.
05-23-2000, 05:01 PM #18pete892Firehouse.com Guest
Everyone is right as usual but the big thing is to recirculate when at the scene. Until you have had a pump freeze up at the scene and can't even get it to shirt back manually to "road" and have to tow it, you have not seen cold weather. Even in warm weather the pump should be recirculated to prevent pump overheat. Check with the pump manufacturer.
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