Honeywell L4081, L6081 Multiple Aquastat® Controllers
High limit, low limit and/or circulator controllers used to regulate boiler water temperature in gas- or oil-fired hydronic heating systems.
• An immersion type liquid-filled sensing element actuates two snap switches.
• One switch operates as a high limit control.
• The other switch operates as a low limit and/or circulator control, depending on the model.
• Controller may be mounted in any positioning and needs no leveling.
• Separate, easy-to-read, calibrated dial and setpoint adjustments for each switch.
• Differential adjustment on low limit or circulator switch.
• All adjustments accessible inside front cover.
• Push-in terminals for quick connecting.
• Single sensing element for easy installation.
• One SPST and one SPDT snap switches act independently at respective temperature settings.
Select a link under the "item" tab below to order.
| Cat # | Insulation Depth | Spud Size | Includes | Differential Temperature | Application: | Mounting | Switching Action |
| L4081A1023 | 1 1/2 in. | 3/4 in. - 14 NPT | — | High limit: 10 F fixed; low limit: 10-25 F adj. | High and Low limit | Horizontal | SPST: High & Low Limit |
| L4081B1013 | 3 in. | 3/4 in. - 14 NPT | — | 10 F fixed | High Limit and Circulator | Horizontal | SPST: High Limit & Circulator |
| L4081B1047 | 1 1/2 in. | 3/4 in. - 14 NPT | — | High limit: 10 F fixed; low limit: 10-25 F adj. | High Limit and Circulator | Horizontal | SPST: High Limit & Circulator |
| L4081B1096 | 3 in. | — | — | 10 F fixed | High Limit and Circulator | Horizontal | SPST: High Limit & Circulator |
| L6081A1010 | 3 in. | 3/4 in. - 14 NPT | 3 in. insertion well. | 10 F fixed | High and Low limit | Horizontal | — |
| L6081A1036 | 1 1/2 in. to 4 in. | 3/4 in. - 14 NPT | — | High limit: 10 F fixed; low limit: 10-25 F adj. | High and Low limit | Horizontal | — |
| Dimensions, Approximate: | 3 7/8 in. high x 4 1/8 in. wide x 2 3/4 in. deep (98 mm high x 105 mm wide x 70 mm deep.) | ||
| Electrical Ratings: | Transformer Load: 360 VA | ||
| Maximum Ambient Temperature: | 150 F at switches; 265 F at sensing element (66 C at switches; 129 C at sensing element) | ||
| Operating Range, High Limit: | 130 F to 240 F (54 C to 116 C) | ||
| Operating Range, Low Limit: | 110 F to 220 F (43 C to 104 C) | ||
| Operating Humidity Range (% RH): | 0 to 95% RH, non-condensing | ||
| Approvals: | |||
| Canadian Standards Association: | Certified: File No. LR95329-1 | ||
| Underwriters Laboratories Inc. | UL Listed: File No. MP466, Vol. 12, Sec. 4, Guide No. MBPR2 | ||
