Honeywell RM7838C1012 User Manual

RM7838B, RM7838C 7800 SERIES RELAY MODULES
32-00211—01 26
NOTE: 10 seconds is the minimum test time allowed. If
your calculations are less than 10 seconds, enter
10 seconds.
For Example:
We have a 2.5 MBTU burner with 2 psi valve train inlet
pressure. The upstream valve is a proof-of-closure V5044
with a solenoid V4295 valve downstream. We have a 2 in.
NPT pipe, 1-3/4 ft long, between the valves.
Table 11. VPS Worksheet Example.
a
Divide inches w.c. by 27.7 to get psi.
b
Divide Btuh by 1000 to get cf/hr for natural gas or by 2550 to get cf/hr for LP gas.
Calculation of Valve Train Volume:
X = V1 + V2 + (A x L ÷ 144)
X = 0.0218 + 0.0267 + (3.356 x 1.75 ÷ 144) = 0.0893.
Calculation of Valve Proving Test Time:
Test Time = 187,000 x (P x X ÷ C)
Test Time = 187,000 x (2 x 0.0893 ÷ 2500) = 13.4 secs.
Round up to 14 seconds; enter 14 seconds into the VPS
Setup.
Table 12. V1 Upstream Volumes for Honeywell Valves.
Table 13. V2 Downstream Volumes for Honeywell Valves.
Item Description Information Lookup Table Results Formula Item
V1 Upstream Valve Volume V5055 12 0.0218 V1
V2 Downstream Valve Volume V4295 13 0.0267 V2
D Pipe Size NPT (in.) 2 in. NPT 14 3.356 A
L Pipe Length (ft) 1.75 ft — 1.75 L
P
Valve Inlet Pressure (psig)
a
2— 2P
C
Burner Maximum Firing (cf/hr)
b
2.5 mbtu — 2500 C
Pipe Size
NPT (inches) V4295 V4297A1013 V4297A1005 V48 V5055 V5097A1004 V5097A1012
3/80.0002——————
1/20.0002——————
3/4 0.0008 0.0093 0.0090 0.0010 0.0046 0.0066 —
1 0.0009 0.0093 0.0090 0.0010 0.0046 0.0066 —
1-1/4 0.0045 0.0093 0.0090 0.0035 0.0046 0.0066 —
1-1/2 0.0045 0.0093 — 0.0035 0.0218 0.0066 —
2 0.0089 0.0093 — 0.0048 0.0218 0.0066 0.0285
2-1/2 0.0441 — — 0.0048 0.0227 — 0.0285
3 0.0441 — — 0.0048 0.0227 — 0.0285
4 ————0.0779——
Pipe Size
NPT (inches) V4295 V4297A1013 V4297A1005 V48 V5055 V5097A1004 V5097A1012
3/80.0011——————
1/20.0011——————
3/4 0.0026 0.0282 0.0232 0.0048 0.0067 0.0093 —
1 0.0036 0.0282 0.0232 0.0048 0.0067 0.0093 —
1-1/4 0.0148 0.0282 0.0232 0.0110 0.0067 0.0093 —
1-1/2 0.0148 0.0282 — 0.0110 0.0238 0.0093 —
2 0.0267 0.0282 — 0.0184 0.0238 0.0093 0.0303
2-1/2 0.0554 — — 0.0184 0.0245 — 0.0303
3 0.0554 — — 0.0184 0.0245 — 0.0303
4 ————0.0801——

Honeywell RM7838C1012 Specifications

General

Brand	Honeywell
Model	RM7838C1012
Category	Control Unit
Language	English