Steam Pressure Too High/Settings?

Vermonter

Looks almost exactly like the one I'm about to replace.

I found the pressuretrol to be pretty inaccurate, especially at the low end of the scale. I lowered the setting to the point where the head of the screw *just* began to lift away from the body of the pressuretrol, then turned it back down a half a turn. I also set the cut-out dial as low as possible; 1psi.

I've also found the pressure gauge inaccurate, even at no load it reads about a pound and a half.

Any of the pros here know why it would have a 30psi gauge? is that standard or required? I'd like to replace mine with a 0-30 in.H2O gauge to really get a good reading.

Pat_24

I just ordered your book and wish I had it right now. Here’s my problem that I’d like to run past you.

I have a 100-yr old house gambrel roof 1500 sq foot 3-story (original finished attic with some insulation.) The heating system is a 1-pipe steam with some original and some downsized 40’s cast iron radiators.

The boiler is a 1992 Weil-McClain EG-45 PIDN. The thermostat is a programmable Honeywell CT 3600 with the temps set at 66F morning, 68F Day/Evening and 58F Night. With real winter weather finally setting in the system is definitely unbalanced.

The radiator in the room with the thermostat is a large 2x4x2 window-seat style. When this one is turned on, the thermostat hits the set point too fast and the rest of the radiators in the house don’t heat up all the way across and put out puny amounts of heat.

When this large rad is turned off, the rest of the radiators heat up fine. Three bedrooms now over-heat. Two of the rads have Danfoss thermostatic vents on them. One appears to work, but only if the setting is turned all the way down to”1”. The other doesn’t appear to work at all. Last night the temperature in this bedroom got to a tropical 80F even though the main part of the house was set at 68 and maintained that temperature fairly well.

I think the pressure in my system is too high. It looks like I have a Honeywell pressuretrol controller PA 404A (additive differential). I attached pics and settings.

Am I correct that the number on the dial should line up with the vertical black line and that I should set it at 1 (or lower) rather than the current 2.5 ?

Do I do this with the heat shut off and the pressure gauge at 0?

Also, I checked an older posting about the Danfoss TRVs so I’m thinking that if I tackle the pressure the non-functioning one should start working?

http://forums.invision.net/Thread.cfm?CFApp=2l.&&Message_ID=215967&_#Message215967

Any other suggestions on tackling the problem? I’m used to maintaining the steam systems in the other two homes I’ve lived in, so I’m confident that I can do reasonable DIY with some guidance. Thanks all!

mel rowe

Pat, I'm sure you will get many helpful responses from this site. In preparation,I suggest that you find your main vents and determine what type you have. That is always a good place to start, and pictures always help. Also, find out what size mains you have and measure the length of each. From this info, can determine if venting is adequate, and then you can move on to other things.

Steamhead (in transit)

I'll second that

but to get back to your Pressuretrol, you're right- turn the white dial to 1, and the sliding pointer to 0.5.

If the boiler then short-cycles, and the system air venting is OK, the boiler is oversized or overfired.

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ttekushan_3

ummm

> I just ordered your book and wish I had it right

> now. Here’s my problem that I’d like to run past

> you.

>

> I have a 100-yr old house gambrel roof

> 1500 sq foot 3-story (original finished attic

> with some insulation.) The heating system is a

> 1-pipe steam with some original and some

> downsized 40’s cast iron radiators.

>

> The

> boiler is a 1992 Weil-McClain EG-45 PIDN. The

> thermostat is a programmable Honeywell CT 3600

> with the temps set at 66F morning, 68F

> Day/Evening and 58F Night. With real winter

> weather finally setting in the system is

> definitely unbalanced.

>

> The radiator in the

> room with the thermostat is a large 2x4x2

> window-seat style. When this one is turned on,

> the thermostat hits the set point too fast and

> the rest of the radiators in the house don’t heat

> up all the way across and put out puny amounts of

> heat.

>

> When this large rad is turned off, the

> rest of the radiators heat up fine. Three

> bedrooms now over-heat. Two of the rads have

> Danfoss thermostatic vents on them. One appears

> to work, but only if the setting is turned all

> the way down to”1”. The other doesn’t appear to

> work at all. Last night the temperature in this

> bedroom got to a tropical 80F even though the

> main part of the house was set at 68 and

> maintained that temperature fairly well.

>

> I

> think the pressure in my system is too high. It

> looks like I have a Honeywell pressuretrol

> controller PA 404A (additive differential). I

> attached pics and settings.

>

> Am I correct that

> the number on the dial should line up with the

> vertical black line and that I should set it at 1

> (or lower) rather than the current 2.5 ?

>

> Do

> I do this with the heat shut off and the pressure

> gauge at 0?

>

> Also, I checked an older posting

> about the Danfoss TRVs so I’m thinking that if I

> tackle the pressure the non-functioning one

> should start

> working?

>

> http://forums.invision.net/Thread.cfm?

> CFApp=2l.&&Message_ID=215967&_#Message215967

>

> An

> y other suggestions on tackling the problem? I’m

> used to maintaining the steam systems in the

> other two homes I’ve lived in, so I’m confident

> that I can do reasonable DIY with some guidance.

> Thanks all!

ttekushan_3

ummm

even with the diff and cut-in you show, there's no way your pressure gauge should be reading nearly 6lbs!

The pressuretrol and gauge should be removed and the pigtail thoroughly cleaned along with the bottom of the controls. For some reason the placement of the EG pigtail in relationship to the steam output on top packs those pigtails with "stuff."

I think the pressure problem will disappear after this.

One more thing. Put a vent on the large radiator with a very small orifice for slow venting. That will help equalize temps. Use maybe a gorton #4 or a maid-o-mist #4 or a hoffman #40 or and adjustable hoffman 1A. Others may be appropriate, but don't buy one off the shelf if you don't know the venting rate.

Terry

brucewo1b

Vermonter

Gauge needs to be twice working pressure and your working pressure is 15PSI per relief valve, nothing preventing you from adding a tee and using a seond gauge thouugh.

PatG

Thanks with More Qustions

So I made the changes and let the system run for the two days. The pressuretrol is lowered to .5psi cut-in and 1 differential. Now the psi gauge doesn’t move off the pin or register—but I’m still getting good steam

During the morning recovery all the rads (even on the third floor) heat up well and evenly. The non-functioning Danfoss TRV now seems to be working, although still running a bit warm—70-72 when the main thermostat is set at 66-68 and the operator is turned to 2 with the air vent opened only slightly passed closed. Any thoughts?

The other Danfoss TRV is right on the button—room temperature is 68 with the operator set at 3 and the vent opened all the way. However, during the morning heat-up the air vent gurgles and spits a lot of moisture, which it didn’t do before. Because the radiator space is tight, the configuration is like the convector setup (see pic and data sheet) http://na.heating.danfoss.com/PCMPDF/RA2000 1PS Datasheet.pdf

Is the configuration the problem? I’m thinking that I could add an elbow to the one coming out of the rad so that the valve body could be turned more toward the corner and be horizontal. The radiator seemed to be pitched ok.

Should I be concerned about short cycling? Once the daytime temperature is hit after the morning recovery, the boiler fires up for about 3-4 minutes about every 40 minutes. All the rads get warm but don’t heat up completely all the way or as hot as the morning and evening recovery cycles. But the set thermostat temperature is maintained and the house seems even and comfortable. For the evening heat-up, we then get another good bit of steam just like the morning and then the 40-minute cycling repeats. Does this seem like the amount of cycling that should be happening?

I looked carefully and discovered that we don’t have any vents off the main pipes. Should I be concerned if everything else seems to be working ok?

Thanks all for your advice!

PatG

Thanks and more questions

So I made the changes and let the system run for the two days. The pressuretrol is lowered to .5psi cut-in and 1 differential. Now the psi gauge doesn't move off the pin or register, but I'm still getting good steam.

During the morning recovery all the rads (even on the third floor) heat up well and evenly. The non-functioning Danfoss TRV now seems to be working, although still running a bit warm--70-72 when the main thermostat is set at 66-68 and the operator is turned to 2 with the air vent opened only slightly passed closed. Any thoughts?

The other Danfoss TRV is right on the button--room temperature at 68 with the operator set at 3 and the vent opened all the way. However, during the morning heat-up the air vent gurgles, bubbles and spits a lot of moisture, which it didn't do before. Because the radiator-to-wall space is tight, the configuration is like the convector setup (see pics and data sheet)

http://na.heating.danfoss.com/PCMPDF/RA2000 1PS Datasheet.pdf

Is the configuration the problem? I'm thinking that I could add an elbow to the one coming out of the rad so that the valve body could be turned more toward the corner and be more horizontal. The radiator seemed to be pitched ok.

Should I be concerned about short cycling? Once the daytime temperature is hit after the morning recovery, the boiler fires up for about 3-4 minutes about every 40 minutes. All the rads get warm but don't heat up completely all the way or as hot as the morning and evening recovery cycles. But the set thermostat temperature is maintained and the house seems even and comfortable. For the evening heat-up, we then get another good bit of steam just like the morning and then the 40-minute cycling repeats. Does this seem like the amount of cycling that should be happening?

I looked carefully and discovered that we don't have any vents off the main pipes. Should I be concerned if everything else seems to be working ok?

Thanks all for your advice!

Steamhead (in transit)

The TRVs should have slower vents

try a Hoffman #41 or similar. Fast vents can allow the rad to overheat before the TRV can react.

You should definitely be concerned about the lack of main vents, even though you think the system is working OK. Measure the length and diameter of each steam main so we can tell you what you need. You'll definitely notice the difference after you install the proper main vents.

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Jamie Hall

cycles

your description of the cycling doesn't sound bad to me at all -- I only wish the boiler in my house could maintain the temp. with a 3 to 4 minute cycle every 40 minutes... oh well.